P24-194 SC Organic light emitting device The present invention relates to an organic electroluminescent device (OLED and organic light emitting device is interchangeable) comprising an anode, a cathode and at least one light emitting layer, wherein the light emitting layer comprises at 5 least one emitter and a host system comprising at least two host materials, a hole- transporting host material and an electron-transporting host material, that are chosen to lower the capacitance of the OLED which leads to faster on- and off- switching times. 10 While traditional device parameters such as colour, voltage, efficiency, or stability have been in focus of material development in the past years now the capacitance is gaining more and more interest especially as OLED displays aim for high picture refresh-rates. 15 In this context, Noguchi, Brütting and coworkers showed in Synthetic Metals 288 (2022), 117101, Figure 7b, that the capacitance of simple bilayer OLEDs can be tuned by materials exhibiting spontaneous orientation polarization. This means that during the material evaporation process the electrical dipoles of the molecules can show a certain degree of alignment with respect to the evaporation direction 20 resulting for example in case of the well-known emitter Alq3 in the tendency to have the negative end of the dipoles at the side of the Alq3 layer towards the substrate while the positive ends of the dipoles are pointing towards the vacuum. In the present invention we implement the sign convention of the resulting layer 25 polarity such that a material like Alq3 has a negative surface charge density (SCD < 0). The question of sign convention arises as one could either define the negative ends of the dipoles at the bottom of the evaporated layer as the relevant SCD (surface charge density) or the positive ends of the dipoles at the top of the layer, but the magnitude of the surface charge on bottom or top is identical as there is no 30 net charge in the evaporated layer consisting of neutral molecules. An example for a host/transport material with SCD < 0 according to this convention is TPBi (1,3,5-tris(1-phenyl-1H-benzo[d]imidazole-2-yl)benzene), while an example of a host/transport material with SCD > 0 is 6F-2TRZ (2,2-bis[4-(4,6-diphenyl-1,3,5- 35 triazin-2-yl)phenyl]hexafluoropropane), both materials are shown in Nature
P24-194 SC Materials, VOL 21, July 2022, 819 to 825 (but with the opposite sign convention for the SCD in Table 1 therein). The physical unit for SCD is milli-Coulomb per square meter (mC/m2). In Example 9 of US 2021/391544 A1 a mixed host system with a weakly positive 5 SCDhost is disclosed. In WO 2024/170609 A1 it is shown that the SCD of emitters and hosts impact color- stability in multi-EML tandem stacks. Therein a method is defined how to measure SCD of single materials based on impedance spectroscopy of concentration series. 10 A similar method for measuring SCD of emitter materials is applied in the present application and a slight modification of it for measuring SCD of single hosts is presented in the present application. It should be noted that an equivalent method to determine SCD often used in the 15 literature is a Kelvin probe measurement of the giant surface potential for increasing layer-thickness of the evaporated material. The resulting slopes of the giant surface potential versus film thickness in mV/nm are proportional to the SCD (see Synthetic Metals 288 (2022), 117101, Figure 7c). Materials like Alq3 or TPBi which we define here as having SCD < 0 result in a positive giant surface potential slope. 20 The giant surface potential slope (GSPS) is proportional to the SCD and the parameters may be used equivalently : ^^^ = −^^^^ ⋅ ^^^^. Here, ^^ refers to the permittivity constant with a value of ~8.854∙10-12 C/(V∙m), ^^refers to the relative permittivity of the investigated material with a value of ~3 for most organic materials used in OLEDs. 25 As an example, e-TMM1 shown in table 1 with SCD =-1.43 mC/m2 would have GSPS=+54 mV/nm while e-TMM11 shown in table 3 with SCD=+2.51 mC/m2 would have GSPS=-95 mV/nm. When investigating the capacitance of full OLED stacks, it has been surprisingly 30 found that in a mixed host system the surface charge density of the individual hosts and their concentrations combined with the surface charge density of the emitter strongly impact the capacitance signal of the full OLED stack. As a figure of merit for the capacitance the area under the capacitance vs voltage 35 curve of the full OLED stack has been measured. It has been aimed to minimize this
P24-194 SC area in order to speed up OLED switching times according to the well-known plate- capacitor time-constant being proportional to the product of capacitance and resistance. Thus, smaller capacitance leads to smaller time-constants and faster OLED switching. 5 The present invention thus relates to an organic light emitting device comprising: - an anode; - a cathode, arranged opposite to the anode; - at least one light emitting layer arranged between the anode and the cathode; wherein the at least one light emitting layer comprises beside at least one 10 emitter EM1 having a surface charge density SCDEM1, a host system comprising at least two host materials, wherein the first host material is a hole- transporting host material h-TMM having a surface charge-density SCDH1 and the second host material is an electron-transporting host material e-TMM having a surface charge-density SCDH2; 15 wherein the surface charge-density of the host system SCDhost is determined according to the following formula: ^^^^^^^ = (∑^ ^^^ ^^^n ∗ ^^)/(∑^ ^^^ ^n ) 20 wherein: n = 1 to N is the number of the different host materials used, cn is the concentration of the different host materials in % by volume, and SCDn is the individual SCD of host n; characterized in that the surface charge-density of the host system SCDhost is 25 greater than 0.5 mC/m2, preferably SCDhost > 1.0 mC/m2, more preferably SCDhost > 1.5 mC/m2 and most preferably SCDhost > 2.0 mC/m2. The different SCDn are determined according to the method as described in Part 1 of the working examples of the present application. 30 In case of two host materials in the host system, n is 2. These positive SCD values (SCDs is interchangeable) are found to lower the area under the capacitance-voltage curve thus leading to faster switching times of the full OLED pixel. However, most literature-known and industry-relevant OLED materials 35 have negative SCDs, thus the present invention aims to improve the capacitance by
P24-194 SC mixed host systems having positive SCD as described before, or preferably described before. As utilized herein, the term “and/or” or “or” may include any and all combinations of one or more of the associated listed items. Throughout the disclosure, the 5 expression such as “at least one of”, “one of”, and ”selected from”, when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. As utilized herein, the term “hole-transporting host material” is synonymously used 10 with the term “hole-transporting material” or “hole-transport material” or “hole- transport host material”. As utilized herein, the term “electron-transporting host material” is synonymously used with the term “electron-transporting material” or “electron-transport material” or “electron-transport host material”. 15 Preferably, the surface charge-density (SCD) of at least one host material is < 0 mC/m2. Also preferably, the surface charge-density (SCD) of at least one host material is > 0 20 mC/m2. Furthermore preferably, the SCDEM1 of the emitter EM1 is less than 0 mC/m2 (SCDEM1 < 0 mC/m2), preferably < -5 mC/m2, more preferably < -10 mC/m2 and most preferably < -15 mC/m2. 25 Preferably, at least one host material has a HOMO energy level of from -5.0 eV to -5.5 eV. Also preferably, at least one host material has a LUMO energy level of from -2.4 eV 30 to -2.8 eV. Furthermore preferably, at least one host material has a HOMO energy level of from -5.0 eV to -5.5 eV and at least another host material has a LUMO level of from -2.4 eV to -2.8 eV. 35
P24-194 SC Preferably, the at least two host materials have a triplet energy level T1 greater than +2.2 eV (T1 > +2.2 eV). Preferably, the at least one emitter and the at least two host materials have a glass transition temperature Tg of greater than 110°C (Tg > 110°C), determined according 5 to DIN 51005 (version 2005-08). In a preferred embodiment of the invention, at least one host material is at least partially, or fully deuterated. In the present disclosure, "D" or "D atom" denotes deuterium. The degree of 10 deuteration, expressed in mol%, means the proportion of H atoms that are replaced by deuterium. Since deuterated compounds are often a mixture of compounds that differ in the exact position and the exact proportion of D atoms, the degree of deuteration denotes the average proportion of H atoms that are replaced by D. With a degree of deuteration of 50 mol%, an average of 50 mol% of the H atoms in the 15 compound are replaced by D, so that the degree of deuteration is average. Preferably, the at least two host materials are at least partially, or fully deuterated. More preferably, the at least two host materials are fully deuterated. In one preferred embodiment, the light emitting layer has an emission maximum 20 wavelength ʎR of from 590 to 660 nm. Therefore, the emitting layer is a red emitting layer. Preferably, the layer having an emission maximum wavelength ʎR of from 590 to 660 nm comprises at least one emitter selected from red phosphorescent emitters. 25 More preferably, the layer having an emission maximum wavelength ʎR of from 590 to 660 nm comprises at least one emitter selected from red phosphorescent emitters and a host system, where the host system comprises at least two host materials, wherein one host material is a hole-transporting host material, and the other host 30 material is an electron-transporting host material. Preferably, the at least one emitter, in the layer having an emission maximum wavelength ʎR of from 590 to 660 nm, is present in a proportion of 0.5 to 30%, preferably 0.5 to 20%, more preferably 1 to 10%, and particularly preferably 1 to 5%. 35
P24-194 SC Preferably, the host system, in the layer having an emission maximum wavelength ʎR of from 590 to 660 nm, is present in a proportion of 70 to 99.5%, preferably 80 to 99.5%, more preferably 90 to 99%, and particularly preferably 95 to 99%. In the present application, proportions are given as percent by volume due to the 5 fact that the materials or material mixtures are applied from the gas phase. Consequently, the expression “%” as used in the present application means “% by volume”. The person skilled in the art, in the context of his common knowledge in the art, is 10 able to identify suitable phosphorescent emitters with appropriate SCD without any great effort as explained in Jurow et al., Nature Materials, Vol 15, January 2016. Examples of suitable red phosphorescent emitters are the compounds disclosed in WO2008/109824, WO2008/078800, US2010/0133524, US2012/0181511, 15 WO2010/033550, US2015/0295198, US2016/0093808, US2018/097187, US2015/0295199, US2020/0127212 or US2020/0111977. Preferably, the red phosphorescent emitter, in the light emitting layer having an emission maximum wavelength ʎR, is selected from compounds of formula (M1): 20 25
, where M is selected from Ir or Pt; 30 LR is a bidentate ligand coordinating by one N- and one C-atom; n is a number equal to 1, if M is Pt, and to 2, if M is Ir; RL1, RL2, RL3 are on each occurrence, identically or differently, selected from H, D, F, a straight-chain alkyl group having 1 to 40 C atoms or a branched or cyclic alkyl 35
P24-194 SC having 3 to 40 C atoms, each of which may be substituted by one or more radicals RL; RL stands on each occurrence, identically or differently, for D, F, CN, a straight- chain alkyl, alkoxy or thioalkyl group having 1 to 20 C atoms or branched or cyclic 5 alkyl, alkoxy or thioalkyl group having 3 to 20 C atoms, where one or more H atoms may be replaced by D or F. More preferably, the red phosphorescent emitter, in the light emitting layer having an emission maximum wavelength ʎR, is selected from compounds of formula (M1-1): 10 15
, where LR, RL1, RL2, RL3 have the same meaning as above. Preferably, LR is a ligand of formula (LR-1), 20 25
, where the dashed bonds indicates the bonds to the iridium atom; and the ring A1, 30 including the nitrogen atom represented in (LR-1), represents a heteroaryl ring having 5 to 20 aromatic ring atoms, which may in each case be substituted by one or more radicals RA1; and the ring B1 represents an aryl or heteroaryl ring having 5 to 20 aromatic ring atoms, which may in each case be substituted by one or more radicals RB1; 35
P24-194 SC RA1, RB1 are the same or different at each instance and is D, F, N(RR)2, ORR, SRR, CN, Si(RR)3, B(ORR)2, a straight-chain alkyl group having 1 to 20 carbon atoms or or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl may in each case be substituted by one or more RR radicals and where one or more nonadjacent CH2 groups may be replaced by Si(RR)2, O, S or an aromatic or 5 heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more RR radicals; at the same time, two RA1 radicals, two RB1 radicals and/or one RA1 radical and one RB1 radical together may also form a ring system; 10 RR is the same or different at each instance and is H, D, F, N(RR´)2, CN, Si(RR´)3, B(ORR´)2, a straight-chain alkyl group having 1 to 20 carbon atoms a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, may in each case be substituted by one or more RR´ radicals and where one or more nonadjacent CH2 groups may be replaced by Si(RR´)2, O, S, or an aromatic or heteroaromatic ring 15 system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more RR´ radicals; at the same time, two or more RR radicals together may form a ring system; RR´ is the same or different at each instance and is H, D, F or an aliphatic organic 20 radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F. More preferably, LR is a ligand of formula (LR-1-1): 25 30
, where the symbols "*" indicate the bonding positions to the iridium atom; and 35
P24-194 SC XR is the same or different at each instance and is CH, CRA1, N or two adjacent groups XR form a condensed aryl or heteroaryl ring having 5 to 20 aromatic ring atoms; YR is the same or different at each instance and is CH, CRB1, N or two adjacent 5 groups YR form a condensed aryl or heteroaryl ring having 5 to 20 aromatic ring atoms; RA1, RB1 have the same definition as above. 10 More preferably, when two adjacent groups XR form a condensed aryl or heteroaryl ring having 5 to 20 aromatic ring atoms, then the condensed aryl or heteroaryl ring is a ring of formula (CyR-1), (CyR-2), (CyR-3), (CyR-4) or (CyR-5), 15 20
where, in (CyR-1) to (CyR-5), the dashed bonds represent the bonding positions to the adjacent ring in formula (LR-1-1), 25 ZR is the same or different at each instance and is CH, CRA1 or N, with the proviso that at most two symbols ZR per ring are N; ER is S or O; 30 RA1 has the same meaning as above. Examples of suitable red phosphorescent emitters are depicted in the table below: 35
P24-194 SC 5 10
In a further preferred embodiment, the emitting layer has an emission maximum wavelength ʎBGY from 450 to 585 nm. Therefore, the emitting layer is a blue, green or yellow emitting layer. 15 Preferably, the layer having an emission maximum wavelength ʎBGY of from 450 to 585 nm comprises at least one emitter selected from blue, green, and yellow fluorescent or phosphorescent emitters, preferably selected from green fluorescent, and green phosphorescent emitters. More preferably at least one emitter is a green 20 phosphorescent emitter, selected from iridium and platinum complexes. More preferably, the layer having an emission maximum wavelength ʎBGY of from 450 to 585 nm comprises at least one emitter selected from blue, green, and yellow fluorescent or phosphorescent emitters and a host system having a surface charge 25 density of the mixed host SCDhost > 0.5 mC/m2 as described before or as preferably described before. Preferably, the host system, in the layer having an emission maximum wavelength ʎBGY of from 450 to 585 nm, is present in a proportion of 60 to 99.5%, preferably 75 30 to 97%, and more preferably 85 to 95%. Preferably, the at least one emitter, in the layer having an emission maximum wavelength ʎBGY of from 450 to 585 nm, is present in a proportion of 0.5 to 40%, preferably 3 to 25%, and more preferably 5 to 15%. 35
P24-194 SC The person skilled in the art, in the context of his common knowledge in the art, is able to identify suitable blue, green, and yellow fluorescent and phosphorescent emitters without any great effort. Examples of suitable blue-fluorescent emitters are disclosed in WO 2021/090932, 5 WO 2020/054676, WO 2020/017931, WO 2020/218079, WO 2018/212169, WO 2019/235452, US 10,249,832 and WO 2021/014001. Examples of blue phosphorescent emitters are disclosed in Sungho Nam et al, Adv. Sci.2021, 2100586 and Eungdo Kin et al, Sci. Adv.2022, 8, eabq 1641, EP 3435438 A2, CN 109111487, US 2020/0140471 A, KR 2020108705, US 2019/0119312 A, US 10 2020/0411775 A, US 2022/115607 A, US 2022298193 A, US2016072082 A and US 2022271236 A. Examples of suitable yellow emitters are the yellow phosphorescent emitters disclosed in US 2020/0111977, WO2010/028151, EP1239526, TWI618710 and JP2017/048184. Examples of suitable green emitters are the green phosphorescent emitters disclosed in US2001/0019782, WO2010/028151, 15 US2001/0019782, WO2010/028151, EP1239526, US2010/0244004, WO2000/070655, US2014/0131676, US2014/0231755, EP3381927, US2018/0287070, EP3623443, DE102020101561, WO2009/116456 and WO2020/165064. 20 Very suitable blue phosphorescent metal complexes are the compounds of formula (Pt-1) as defined below: 25
30 , where: Y1, Y2, Y3, Y4, Y5 stand, on each occurrence identically or differently, for a group CRY or N; or Y1-Y2 and/or Y3-Y4 or Y4-Y5 may form a condensed aryl or heteroaryl ring having 5 to 18 aromatic ring atoms, which may in each case also be 35 substituted by one or more radicals RP;
P24-194 SC E50 stands for on each occurrence, identically or differently, for C(RC0)2, NRN0, O or S; Ar50 is, on each occurrence, identically or differently, an aromatic or heteroaromatic 5 ring system having 5 to 60, which may in each case also be substituted by one or more radicals RP; Ar51, Ar52, Ar53 represent, identically or differently, a condensed aryl or heteroaryl ring having 5 to 18 aromatic ring atoms, which may in each case also be substituted 10 by one or more radicals RP; RY stand on each occurrence, identically or differently, for a radical selected from H, D, F, Cl, Br, I, CHO, CN, C(=O)Ar, P(=O)(Ar)2, S(=O)Ar, S(=O)2Ar, N(RP)2, N(Ar)2, NO2, Si(RP)3, B(ORP)2, OSO2RP, a straight-chain alkyl, alkoxy or thioalkyl group 15 having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals RP, where in each case one or more non-adjacent CH2 groups may be replaced by RPC=CRP, C≡C, Si(RP)2, Ge(RP)2, Sn(RP)2, C=O, C=S, C=Se, P(=O)(RP), SO, SO2, O, S or CONRP and where one or more H atoms may be replaced by D, F, Cl, Br, I, 20 CN or NO2, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals RP, and an aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals RP; where two radicals RY may form an aliphatic, aromatic or heteroaromatic ring system together, which may be substituted by one or more 25 radicals RP; RC0 stand on each occurrence, identically or differently, for a radical selected from H, D, a straight-chain alkyl group having 1 to 40 C atoms, which may be substituted by one or more radicals RP, an aryl or heteroaryl group having 6 to 18 aromatic ring 30 atoms, which may in each case be substituted by one or more radicals RP; where two radicals RC0 may form an aliphatic, aromatic or heteroaromatic ring system together, which may be substituted by one or more radicals RP; RN0 stand on each occurrence, identically or differently, for a radical selected from 35 H, D, F, a straight-chain alkyl group having 1 to 40 C atoms or branched or a cyclic
P24-194 SC alkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals RP, and where one or more H atoms may be replaced by D, F or CN, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals RP; 5 RP stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CHO, CN, C(=O)Ar, P(=O)(Ar)2, S(=O)Ar, S(=O)2Ar, N(R´)2, N(Ar)2, NO2, Si(R´)3, B(OR´)2, OSO2R´, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched or a cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R´, where in each 10 case one or more non-adjacent CH2 groups may be replaced by R´C=CR´, C≡C, Si(R´)2, Ge(R´)2, Sn(R´)2, C=O, C=S, C=Se, P(=O)(R´), SO, SO2, O, S or CONR´ and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO2, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R´, or an aryloxy group 15 having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R´; where two radicals RP may form a mono- or polycyclic, aliphatic ring system, aromatic or heteroaromatic ring system, which may be substituted by one or more radicals R’; 20 Ar is, on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case also be substituted by one or more radicals R´; R´ stands on each occurrence, identically or differently, for H, D, F, Cl, Br, I, CN, 25 a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 C atoms, where in each case one or more non-adjacent CH2 groups may be replaced by SO, SO2, O, S and where one or more H atoms may be replaced by D, F, Cl, Br or I, or an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms. 30 In accordance with another preferred embodiment, the at least one emitter in the layer having an emission maximum wavelength ʎBGY of from 450 to 585 nm is selected from blue, green, and yellow phosphorescent emitters selected from metal complexes of formulae (1) and (2), 35
P24-194 SC
5 . Lact in formula (1) represents the optically active ortho-metallated bidentate ligand or, in formula (2), the optically active ortho-metallated bidentate sub-ligand. L is the same or different at each instance in formula (1) and represents the optically inactive ortho-metallated bidentate ligands or, in formula (2), the optically inactive 10 ortho-metallated bidentate sub-ligands. V in formula (2) is a bridging unit that joins the sub-ligands Lact and L covalently to one another to form a tripodal hexadentate ligand. Preference is given to the tripodal complexes of the formula (2). The ligand in formula (2) is a hexadentate tripodal ligand having one bidentate sub- 15 ligand Lact and two bidentate sub-ligands L. “Bidentate" means that the particular sub-ligand in the complex coordinates or binds to the iridium via two coordination sites. "Tripodal" means that the ligand has three sub-ligands bonded to the bridge V. Since the ligand has three bidentate sub-ligands, the overall result is a hexadentate ligand, i.e. a ligand which coordinates or binds to the iridium via six coordination 20 sites. The expression "bidentate sub-ligand" in the context of this application means that Lact and L would each be a bidentate ligand if the bridge V were absent. However, as a result of the formal abstraction of a hydrogen atom from this bidentate ligand and the attachment to the bridge, it is no longer a separate ligand but a portion of the hexadentate ligand which thus arises, and so the term "sub- 25 ligand" is used therefor. The bidentate ortho-metallated ligands or sub-ligands Lact and L are described hereinafter. The ligands or sub-ligands Lact and L coordinate to the iridium via one carbon atom and one nitrogen atom or via two carbon atoms. When Lact or L 30 coordinates to the iridium via two carbon atoms, one of the two carbon atoms is a carbene carbon atom. In addition, L is different from Lact since Lact is an optically active ligand or sub-ligand, while L is optically inactive. In a preferred embodiment of the invention, the two ligands or sub-ligands L are identical. 35
P24-194 SC More preferably, each ligand or sub-ligand Lact and L has one carbon atom and one nitrogen atom as coordinating atoms. It is further preferable when the metallacycle which is formed from the iridium and the ligand or sub-ligand Lact and L is a five-membered ring. This is shown 5 schematically hereinafter:
, 10 where N represents a coordinating nitrogen atom and C a coordinating carbon atom, and the carbon atoms shown represent atoms of the ligand or sub-ligand Lact or L. As described above, the structure fragment Ir(L) has a higher triplet energy than the 15 structure fragment Ir(Lact) with the optically active ligand or sub-ligand. This achieves the effect that the emission from the complex comes predominantly from the structure fragment Ir(Lact). In a preferred embodiment of the emitter, the ligands or sub-ligands Lact and L are a 20 structure of the following formulae (L-1) or (L-2), where Lact and L are different from one another and the two ligands or sub-ligands L may be the same or different, but are preferably the same, 25
, 30 where the dotted bond represents the bond of the sub-ligand to the bridge V in formula (2) and is absent for formula (1) and where the other symbols used are as follows: CyC is the same or different at each instance and is a substituted or unsubstituted 35 aryl or heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates in
P24-194 SC each case to the metal via a carbon atom and which is bonded to CyD via a covalent bond; CyD is the same or different at each instance and is a substituted or unsubstituted heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates to the metal 5 via a nitrogen atom or via a carbene carbon atom and which is bonded to CyC via a covalent bond; at the same time, two or more of the optional substituents together may form a ring system; the optional radicals are preferably selected from the R radicals defined 10 below. CyD coordinates via an uncharged nitrogen atom or via a carbene carbon atom, and CyC coordinates via an anionic carbon atom. 15 When two or more of the substituents, especially two or more R radicals, together form a ring system, it is possible for a ring system to be formed from substituents bonded to directly adjacent carbon atoms. In addition, it is also possible that the substituents on CyC and CyD or on the two CyD groups together form a ring, as a result of which CyC and CyD may also together form a single fused aryl or 20 heteroaryl group as bidentate ligand. Preferably, all ligands or sub-ligands Lact and L have a structure of the formula (L-1), or all ligands or sub-ligands Lact and L have a structure of the formula (L-2). Lact is different from L, and the two sub-ligands L are preferably the same. 25 In a preferred embodiment of the present invention, CyC is an aryl or heteroaryl group having 6 to 13 aromatic ring atoms, more preferably having 6 to 10 aromatic ring atoms, most preferably having 6 aromatic ring atoms, which coordinates to the metal via a carbon atom, which may be substituted by one or more R radicals, and 30 which is bonded to CyD via a covalent bond. Preferred embodiments of the CyC group are the structures of the following formulae (CyC-1) to (CyC-19) where the CyC group binds in each case at the position signified by # to CyD and coordinates at the position signified by * to the 35 iridium,
P24-194 SC 5 10 15 20 25
(CyC-18) (CyC-19) (CyC-20) , 30 where the symbols used are as follows: X is the same or different at each instance and is CR or N, with the proviso that at most two symbols X per ring are N; 35
P24-194 SC W is the same or different at each instance and is NR, O, or S; R is the same or different at each instance and is H, D, F, Cl, Br, I, N(R1)2, OR1, SR1, CN, NO2, COOR1, C(=O)N(R1)2, Si(R1)3, B(OR1)2, C(=O)R1, P(=O)(R1)2, S(=O)R1, S(=O)2R1, OSO2R1, a straight-chain alkyl group having 1 to 20 carbon 5 atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R1 radicals and where one or more nonadjacent CH2 groups may be replaced by Si(R1)2, C=O, NR1, O, S or CONR1, or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic 10 ring atoms and may be substituted in each case by one or more nonaromatic R1 radicals; at the same time, two R radicals together may also form a ring system; R1 is the same or different at each instance and is H, D, F, Cl, Br, I, N(R2)2, OR2, SR2, CN, NO2, Si(R2)3, B(OR2)2, C(=O)R2, P(=O)(R2)2, S(=O)R2, S(=O)2R2, 15 OSO2R2, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R2 radicals and where one or more nonadjacent CH2 groups may be replaced by Si(R2)2, C=O, NR2, O, S or CONR2, or an aromatic 20 or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R2 radicals; at the same time, two or more R1 radicals together may form a ring system; R2 is the same or different at each instance and is H, D, F or an aliphatic organic 25 radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F; with the proviso that, when the bridge V is bonded to CyC in formula (2), one symbol X is C and the bridge V is bonded to this carbon atom. When the CyC group is 30 bonded to the bridge V, the bond is preferably via the position marked "o" in the formulae depicted above, and so the symbol X marked "o" in that case is preferably C. The above-depicted structures which do not contain any symbol X marked "o" are preferably not bonded directly to the bridge V, since such a bond to the bridge is not advantageous for steric reasons. 35
P24-194 SC A cyclic alkyl, alkoxy or thioalkoxy group in the context of this invention is understood to mean a monocyclic, bicyclic or polycyclic group. In the context of the present invention, a C1- to C20-alkyl group in which individual hydrogen atoms or CH2 groups may also be replaced by the abovementioned 5 groups is understood to mean, for example, the methyl, ethyl, n-propyl, i-propyl, cyclopropyl, n-butyl, i-butyl, s-butyl, t-butyl, cyclobutyl, 2-methylbutyl, n-pentyl, s- pentyl, t-pentyl, 2-pentyl, neopentyl, cyclopentyl, n-hexyl, s-hexyl, t-hexyl, 2-hexyl, 3- hexyl, neohexyl, cyclohexyl, 1-methylcyclopentyl, 2-methylpentyl, n-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, cycloheptyl, 1-methylcyclohexyl, n-octyl, 2-ethylhexyl, cyclooctyl, 10 1-bicyclo[2.2.2]octyl, 2-bicyclo[2.2.2]octyl, 2-(2,6-dimethyl)octyl, 3-(3,7- dimethyl)octyl, adamantyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, 1,1- dimethyl-n-hex-1-yl, 1,1-dimethyl-n-hept-1-yl, 1,1-dimethyl-n-oct-1-yl, 1,1-dimethyl-n- dec-1-yl, 1,1-dimethyl-n-dodec-1-yl, 1,1-dimethyl-n-tetradec-1-yl, 1,1-dimethyl-n- hexadec-1-yl, 1,1-dimethyl-n-octadec-1-yl, 1,1-diethyl-n-hex-1-yl, 1,1-diethyl-n-hept- 15 1-yl, 1,1-diethyl-n-oct-1-yl, 1,1-diethyl-n-dec-1-yl, 1,1-diethyl-n-dodec-1-yl, 1,1- diethyl-n-tetradec-1-yl, 1,1-diethyl-n-hexadec-1-yl, 1,1-diethyl-n-octadec-1-yl, 1-(n- propyl)cyclohex-1-yl, 1-(n-butyl)cyclohex-1-yl, 1-(n-hexyl)cyclohex-1-yl, 1-(n- octyl)cyclohex-1-yl and 1-(n-decyl)cyclohex-1-yl radicals. An alkenyl group is understood to mean, for example, ethenyl, propenyl, butenyl, pentenyl, 20 cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl or cyclooctadienyl. An alkynyl group is understood to mean, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl or octynyl. An OR1 group is understood to mean, for example, methoxy, trifluoromethoxy, ethoxy, n-propoxy, i- propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy or 2-methylbutoxy. 25 An aryl group in the context of this invention contains 6 to 30 carbon atoms; a heteroaryl group in the context of this invention contains 2 to 30 carbon atoms and at least one heteroatom, with the proviso that the sum total of carbon atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and/or 30 S. Here, an aryl group or heteroaryl group is understood to mean either a simple aromatic ring, i.e. benzene, or a simple heteroaromatic ring, for example pyridine, pyrimidine, thiophene, etc., or a condensed (fused) aryl or heteroaryl group, for example naphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc. Aromatic systems joined to one another by a single bond, for example biphenyl, by 35
P24-194 SC contrast, are not referred to as an aryl or heteroaryl group but as an aromatic ring system. An aromatic ring system in the context of this invention contains 6 to 40 carbon atoms, preferably 6 to 30 carbon atoms, in the ring system. A heteroaromatic ring 5 system in the context of this invention contains 2 to 40 carbon atoms, preferably 2 to 30 carbon atoms, and at least one heteroatom in the ring system, with the proviso that the sum total of carbon atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and/or S. An aromatic or heteroaromatic ring system in the context of this invention shall be understood to mean a system which 10 does not necessarily contain only aryl or heteroaryl groups, but in which it is also possible for two or more aryl or heteroaryl groups to be joined by a nonaromatic unit, for example a carbon, nitrogen or oxygen atom. These shall likewise be understood to mean systems in which two or more aryl or heteroaryl groups are joined directly to one another, for example biphenyl, terphenyl, bipyridine or phenylpyridine. For 15 example, systems such as fluorene, 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ethers, stilbene, etc. shall also be regarded as aromatic ring systems in the context of this invention, and likewise systems in which two or more aryl groups are joined, for example, by a short alkyl group. Preferred aromatic or heteroaromatic ring systems are simple aryl or heteroaryl groups and groups in 20 which two or more aryl or heteroaryl groups are joined directly to one another, for example biphenyl or bipyridine, and also fluorene or spirobifluorene. An aromatic or heteroaromatic ring system which has 5-40 aromatic ring atoms and may also be substituted in each case by the abovementioned R2 radicals or a 25 hydrocarbyl radical and which may be joined to the aromatic or heteroaromatic system via any desired positions is understood to mean especially groups derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, pyrene, chrysene, perylene, fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, triphenylene, fluorene, spirobifluorene, 30 dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans- indenofluorene, cis- or trans-indenocarbazole, cis- or trans-indolocarbazole, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, pyridine, quinoline, isoquinoline, acridine, 35 phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline,
P24-194 SC phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine, hexaazatriphenylene, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, 5 1,5-diazaanthracene, 2,7-diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8- diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorubine, naphthyridine, azacarbazole, benzocarboline, phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 1,2,3- oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 10 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole, or groups derived from a combination of these systems. 15 Preferably, a total of not more than two symbols X in CyC are N, more preferably not more than one symbol X in CyC is N, and most preferably all symbols X are CR, with the proviso that, when the bridge V in formula (2) is bonded to CyC, one symbol X is C and the bridge V is bonded to this carbon atom. 20 Particularly preferred CyC groups are the groups of the following formulae (CyC-1a) 25 30 35
P24-194 SC 5 10 15 20 25
, 30 where the symbols used have the definitions given above and, when the bridge V is bonded to CyC in formula (2), one R radical is absent, and the bridge V is bonded to the corresponding carbon atom. When the CyC group is bonded to the bridge V, the bond is preferably via the position marked "o" in the formulae depicted above, and 35 so the R radical in this position in that case is preferably absent. The above-depicted
P24-194 SC structures which do not contain any carbon atom marked "o" are preferably not bonded directly to the bridge V. Preferred groups among the (CyC-1) to (CyC-19) groups are the (CyC-1), (CyC-3), (CyC-8), (CyC-10), (CyC-12), (CyC-13) and (CyC-16) groups, and particular 5 preference is given to the (CyC-1a), (CyC-3a), (CyC-8a), (CyC-10a), (CyC-12a), (CyC-13a) and (CyC-16a) groups. In a further preferred embodiment of the emitter, CyD is a heteroaryl group having 5 to 13 aromatic ring atoms, more preferably having 6 to 10 aromatic ring atoms, 10 which coordinates to the metal via an uncharged nitrogen atom or via a carbene carbon atom and which may be substituted by one or more R radicals, and which is bonded via a covalent bond to CyC. Preferred embodiments of the CyD group are the structures of the following 15 formulae (CyD-1) to (CyD-18) where the CyD group binds in each case at the position signified by # to CyC and coordinates at the position signified by * to the iridium, 20 25 30 35
P24-194 SC 5 10 15
, where X, W and R have the definitions given above, with the proviso that, when the 20 bridge V in formula (2) is bonded to CyD, one symbol X is C and the bridge V is bonded to this carbon atom. When the CyD group is bonded to the bridge V, the bond is preferably via the position marked "o" in the formulae depicted above, and so the symbol X marked "o" in that case is preferably C. The above-depicted structures which do not contain any symbol X marked "o" are preferably not bonded 25 directly to the bridge V, since such a bond to the bridge is not advantageous for steric reasons. In this case, the (CyD-1) to (CyD-4) and (CyD-7) to (CyD-18) groups coordinate to the iridium via an uncharged nitrogen atom, and (CyD-5) and (CyD-6) groups via a 30 carbene carbon atom. Preferably, a total of not more than two symbols X in CyD are N, more preferably not more than one symbol X in CyD is N, and especially preferably all symbols X are CR, with the proviso that, when the bridge V in formula (2) is bonded to CyD, one 35 symbol X is C and the bridge V is bonded to this carbon atom.
P24-194 SC Particularly preferred CyD groups are the groups of the following formulae (CyD-1a) to (CyD-18a): 5 10 15 20 25 30
, 35
P24-194 SC where the symbols used have the definitions given above and, when the bridge V is bonded to CyD in formula (2), one R radical is absent, and the bridge V is bonded to the corresponding carbon atom. When the CyD group is bonded to the bridge V, the bond is preferably via the position marked "o" in the formulae depicted above, and so the R radical in this position in that case is preferably absent. The above-depicted 5 structures which do not contain any carbon atom marked "o" are preferably not bonded directly to the bridge V. Preferred groups among the (CyD-1) to (CyD-12) groups are the (CyD-1), (CyD-2), (CyD-3), (CyD-4), (CyD-5) and (CyD-6) groups, especially (CyD-1), (CyD-2) and 10 (CyD-3), and particular preference is given to the (CyD-1a), (CyD-2a), (CyD-3a), (CyD-4a), (CyD-5a) and (CyD-6a) groups, especially (CyD-1a), (CyD-2a) and (CyD- 3a). In a preferred embodiment of the emitter, CyC is an aryl or heteroaryl group having 15 6 to 13 aromatic ring atoms, and at the same time CyD is a heteroaryl group having 5 to 13 aromatic ring atoms. More preferably, CyC is an aryl or heteroaryl group having 6 to 10 aromatic ring atoms, and at the same time CyD is a heteroaryl group having 5 to 10 aromatic ring atoms. Most preferably, CyC is an aryl or heteroaryl group having 6 aromatic ring atoms, and CyD is a heteroaryl group having 6 to 10 20 aromatic ring atoms. At the same time, CyC and CyD may be substituted by one or more R radicals. The abovementioned preferred groups (CyC-1) to (CyC-20) and (CyD-1) to (CyD- 18) may be combined with one another as desired. It is necessary here for 25 compounds of the formula (2) that at least one of the CyC or CyD groups has a suitable linkage site to the bridge V, where suitable linkage sites in the abovementioned formulae are identified by "o". It is especially preferable when the CyC and CyD groups mentioned as particularly 30 preferred above, i.e. the groups of the formulae (CyC-1a) to (CyC-20a) and the groups of the formulae (CyD1-a) to (CyD-18a), are combined with one another. It is very particularly preferable when one of the (CyC-1), (CyC-3), (CyC-8), (CyC- 10), (CyC-12), (CyC-13) and (CyC-16) groups, especially the (CyC-1a), (CyC-3a), 35 (CyC-8a), (CyC-10a), (CyC-12a), (CyC-13a) and (CyC-16a) groups, is combined
P24-194 SC with one of the (CyD-1), (CyD-2) and (CyD-3) groups, especially with one of the (CyD-1a), (CyD-2a) and (CyD-3a) groups. Preferred sub-ligands (L-1) are the structures of the formulae (L-1-1) and (L-1-2), and preferred sub-ligands (L-2) are the structures of the formulae (L-2-1) to (L-2-4): 5 10
, 15 where the symbols used have the definitions given above and "o" in compounds of the formula (2) represents the position of the bond to the bridge V, in which case the corresponding X is C. Particularly preferred sub-ligands (L-1) are the structures of the formulae (L-1-1a) 20 and (L-1-2b), and particularly preferred sub-ligands (L-2) are the structures of the formulae (L-2-1a) to (L-2-4a), 25
( - - a) 30 35
P24-194 SC 5
where the symbols used have the definitions given above and "o" in formula (2) 10 represents the position of the bond to the bridge V, in which case the corresponding R radical is absent. When two R radicals of which one is bonded to CyC and the other to CyD together form an aromatic ring system, this can result in bridged ligands or sub-ligands L1 or 15 L2, in which case some of these bridged sub-ligands overall form a single larger heteroaryl group, for example benzo[h]quinoline, etc. The ring between the substituents on CyC and CyD is preferably formed by a group of one of the following formulae (3) to (12): 20 25
, 30 where R1 has the definitions given above and the dotted bonds signify the bonds to CyC or CyD. It is possible here for the unsymmetric groups among those mentioned above to be incorporated in either of the two ways. For example, in the case of the group of the formula (12), the oxygen atom may bind to the CyC group and the carbonyl group to the CyD group, or the oxygen atom may bind to the CyD group 35 and the carbonyl group to the CyC group.
P24-194 SC At the same time, the group of the formula (9) is preferred particularly when this results in ring formation to give a six-membered ring, as shown below, for example, by the formulae (L-21) and (L-22). 5 Preferred ligands which arise through ring formation between two R radicals on the d below: 10 15 20 25 30 35
P24-194 SC 5 10
, where the symbols used have the definitions given above and “o” in formula (2) indicates the position at which the sub-ligand is joined to the V group. 15 In a preferred embodiment of the ligands or sub-ligands of the formulae (L-3) to (L- 30), a total of one symbol X is N and the other symbols X are CR, or all symbols X are CR. 20 In a further embodiment of the emitter, it is preferable if, in the groups (CyC-1) to (CyC-20) or (CyD-1) to (CyD-18) or in the ligands or sub-ligands (L-3) to (L-30), one of the atoms X is N when an R group bonded as a substituent adjacent to this nitrogen atom is not hydrogen or deuterium. This applies analogously to the preferred structures (CyC-1a) to (CyC-20a) or (CyD-1a) to (CyD-18a) in which a 25 substituent bonded adjacent to a non-coordinating nitrogen atom is preferably an R group which is not hydrogen or deuterium. In this case, this substituent R is preferably a group selected from CF3, OCF3, alkyl groups having 1 to 10 carbon atoms, especially branched or cyclic alkyl groups having 3 to 10 carbon atoms, OR1 where R1 is an alkyl group having 1 to 10 carbon 30 atoms, especially a branched or cyclic alkyl group having 3 to 10 carbon atoms, dialkylamino groups having 2 to 10 carbon atoms or aryl or heteroaryl groups having 5 to 10 aromatic ring atoms. These groups are sterically demanding groups. Further preferably, this R radical may also form a cycle with an adjacent R radical. 35
P24-194 SC In a preferred embodiment of the invention, the X group in the ortho position to the coordination to the metal is CR. In this radical, R bonded in the ortho position to the coordination to the metal is preferably selected from the group consisting of H, D, F and methyl. 5 In a further embodiment of the invention, it is preferable if one of the atoms X is N when a substituent bonded adjacent to this nitrogen atom is an R group which is not H or D. In this case, this substituent R is preferably a group selected from CF3, OCF3, alkyl groups having 1 to 10 carbon atoms, especially branched or cyclic alkyl groups having 3 to 10 carbon atoms, OR1 where R1 is an alkyl group having 1 to 10 10 carbon atoms, especially a branched or cyclic alkyl group having 3 to 10 carbon atoms, dialkylamino groups having 2 to 10 carbon atoms or aryl or heteroaryl groups having 5 to 10 aromatic ring atoms. These groups are sterically demanding groups. Further preferably, this R radical may also form a cycle with an adjacent R radical. 15 In a preferred embodiment of the invention, Lact is a ligand or sub-ligand of the following formula (L-39) that coordinates to the iridium via the two positions marked with the letter “D” and which, when the complex is one of formula (2), is bonded to V via the dotted bond, in which case the corresponding X is C: 20 25
, where: 30 K is C or N, with the proviso that one K is C and the other K is N; X is the same or different at each instance and is CR or N; Z is CR', CR or N, with the proviso that exactly one Z is CR' and the other Z is CR or N; where a maximum of one symbol X or Z per cycle is N; 35 R' is a group of the following formula (14) or (15):
P24-194 SC 5 10
where the dotted bond indicates the attachment of the group; R'' is the same or different at each instance and is H, D, F, CN, a straight chain 15 alkyl group having 1 to 10 carbon atoms in which one or more hydrogen atoms may also be replaced by D or F, or a branched or cyclic alkyl group having 3 to 10 carbon atoms in which one or more hydrogen atoms may also be replaced by D or F, or an alkenyl group having 2 to 10 carbon atoms in which one or more hydrogen atoms may also be replaced by D or F; at the same time, two adjacent R'' radicals or two 20 R'' radicals on adjacent phenyl groups together may also form a ring system; or two R'' on adjacent phenyl groups together are a group selected from C(R1)2, NR1, O and S, such that the two phenyl rings together with the bridging group are a carbazole, dibenzofuran or dibenzothiophene, and the further R'' are as defined above; 25 n is 0, 1, 2, 3, 4 or 5. In the case of ring formation by two substituents R'' on adjacent phenyl groups, the result may also be a fluorene or a phenanthrene or a triphenylene. It is likewise 30 possible, as described above, for two R'' on adjacent phenyl groups together to be a group selected from NR1, O and S, such that the two phenyl rings together with the bridging group are a carbazole, dibenzofuran or dibenzothiophene. In a preferred embodiment of the invention, X is the same or different at each 35 instance and is CR. Further preferably, one Z group is CR and the other Z group is
P24-194 SC CR'. More preferably, in the ligand or sub-ligand of the formula (L-39), the X groups are the same or different at each instance and are CR, and at the same time one Z group is CR and the other Z group is CR'. The ligand or sub-ligand L1 preferably has a structure of one of the following formulae (L-39a) or (L-39b), where the linkage to the bridge V for polypodal structures of the formula (L-39) is via the position 5 identified by “o” and no R radical is bonded at this position, 10
, 15 where the symbols used have the meanings given above. More preferably, the sub-ligand L of the formula (L-39) has a structure of one of the following formulae (L-39a') or (L-39b'), where the linkage to the bridge V for polypodal structures of the formula (L-39) is via the position identified by “o” and no 20 R radical is bonded at this position, 25 30
, where the symbols used have the meanings given above. The R radicals in the sub-ligand Lact of the formula (L-39) or formulae (L-39a), (L- 39b), (L-39a') and (L-39d') are preferably selected from the group consisting of H, D, 35 CN, OR1, a straight-chain alkyl group having 1 to 6 carbon atoms, preferably having
P24-194 SC 1 to 3 carbon atoms, or a branched or cyclic alkyl group having 3 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms, each of which may be substituted by one or more R1 radicals, or a phenyl group which may be substituted by one or more nonaromatic R1 radicals. It is also possible here for two or more adjacent R radicals together to form a ring system. 5 In this case, the substituent R bonded to the coordinating atom in the ortho position is preferably selected from the group consisting of H, D, F and methyl, more preferably H, D and methyl and especially H and D. 10 In addition, it is preferable when all substituents R that are in the ortho position to R' are H or D. When the R radicals in the sub-ligand Lact of the formula (L-39) together form a ring system, it is preferably an aliphatic, heteroaliphatic or heteroaromatic ring system. In 15 addition, preference is given to ring formation between two R radicals on the two rings of the sub-ligand Lact, preferably forming a phenanthridine, or a phenanthridine which may contain still further nitrogen atoms. When R radicals together form a heteroaromatic ring system, this preferably forms a structure selected from the group consisting of quinoline, isoquinoline, dibenzofuran, dibenzothiophene and 20 carbazole, each of which may be substituted by one or more R1 radicals, and where individual carbon atoms in the dibenzofuran, dibenzothiophene and carbazole may also be replaced by N. Particular preference is given to quinoline, isoquinoline, dibenzofuran and azadibenzofuran. It is possible here for the fused-on structures to be bonded in any possible position. Preferred sub-ligands L1 with fused-on benzo 25 groups are the structures of the formulae (L-39c) to (L-39j) listed below, where the linkage to the bridge V for polypodal structures of the formula (L-39) is via the position identified by a dotted bond: 30
(L39-c) (L-39d) (L-39e) (L-39f) 35
P24-194 SC 5
(L-39g) (L-39h) (L-39i) (L-39j) , where the ligands may each also be substituted by one or more further R radicals and the fused-on structure may be substituted by one or more R1 radicals. Preferably, there are no fur 1 10 ther R or R radicals present. Preferred sub-ligands Lact of the formula (L-39) with fused-on benzofuran or azabenzofuran groups are the structures of the formulae (L-39k) to (L-39z) listed below, where the linkage to the bridge V for polypodal structures of the formula (L- 15 39) is via the position identified by a dotted bond and no R radical is bonded to this position: 20 25 30
35
P24-194 SC 5 10
, where the ligands may each also be substituted by one or more further R radicals and the fused-on structure may be substituted by one or more R1 radicals. 15 Preferably, there are no further R or R1 radicals present. It is likewise possible for O in these structures to be replaced by S or NR1. Preferred substituents R'' on the groups of the formula (14) or (15) or the preferred 20 embodiments are selected from the group consisting of H, D, CN and an alkyl group having 1 to 4 carbon atoms, more preferably H, D or methyl. The complexes of the formula (2) are complexes having a tripodal hexadentate ligand, where the three sub-ligands Lact and L are covalently bonded to one another 25 by a bridging unit V. These have the advantage over complexes of the formula (1) that they have a higher stability through the covalent linkage of the sub-ligands Lact and L. In a preferred embodiment of the emitter, the bridging unit V is a group of the 30 following formula (16), where the dotted bonds represent the position of the linkage of the sub-ligands Lact and L: 35
P24-194 SC
5 , where: X1 is the same or different at each instance and is CR or N; X2 is the same or different at each instance and is CR or N; A is the same or different at each instance and is CR2-CR2, CR2-O, CR2-NR, 10 group of the following formula (17):
15 , where the dotted bond in each case represents the position of the bond of the bidentate sub-ligands Lact or L to this structure, * represents the position of the linkage of the unit of the formula (17) to the central trivalent aryl or heteroaryl group. 20 When X2 is CR, preferred substituents in the group of the formula (17) are selected from the above-described substituents R. In a preferred embodiment of the emitter, A is the same or different at each instance and is CR2-CR2 or a group of the formula (17). Preference is given here to the 25 following embodiments: - all three A groups are the same group of the formula (17); - two A groups are the same group of the formula (17), and the third A group is CR2-CR2; 30 - one A group is a group of the formula (17), and the two other A groups are the same CR2-CR2 group; or - all three A groups are the same CR2-CR2 group. 35
P24-194 SC What is meant here by "the same group of the formula (17)" is that these groups all have the same base skeleton and the same substitution. Moreover, what is meant by "the same CR2-CR2 group" is that these groups all have the same substitution. When A is CR2-CR2, R is preferably the same or different at each instance and is H 5 or D, more preferably H. The group of the formula (17) is an aromatic or heteroaromatic six-membered ring. In a preferred embodiment of the emitter, the group of the formula (17) contains not more than one heteroatom in the aryl or heteroaryl group. This does not mean that 10 any substituents bonded to this group cannot also contain heteroatoms. In addition, this definition does not mean that formation of rings by substituents does not give rise to fused aromatic or heteroaromatic structures, for example naphthalene, benzimidazole, etc. The group of the formula (17) is preferably selected from benzene, pyridine, pyrimidine, pyrazine and pyridazine. 15 Preferred embodiments of the group of the formula (17) are the structures of the following formulae (18) to (25): 20 25
, where the symbols used have the meanings given above. Particular preference is given to the optionally substituted six-membered aromatic rings and six-membered 30 heteroaromatic rings of the formulae (18) to (22). Very particular preference is given to ortho-phenylene, i.e. a group of the formula (18). At the same time, as also detailed above in the description of the substituent, it is also possible for adjacent substituents together to form a ring system, such that fused structures, including fused aryl and heteroaryl groups, for example 35
P24-194 SC naphthalene, quinoline, benzimidazole, carbazole, dibenzofuran or dibenzothiophene, can form. Stated hereinafter are preferred embodiments of the bridgehead V, i.e. the structure of the formula (16). Preferred embodiments of the group of the formula (16) are the 5 structures of the following formulae (26) to (29): 10 15 20
, where the symbols used have the meanings given above. More preferably, all substituents R in the central ring of the formulae (26) to (29) are 25 H, and so the structures are preferably selected from the formulae (26a) to (29a) 30 35
P24-194 SC 5 10 15 ,
More preferably, the groups of the formulae (26) to (29) are selected from the structures of the following formulae (26b) to (29b): 20 25 30
35 ,
P24-194 SC where R is the same or different at each instance and is H or D, preferably H. There follows a description of preferred substituents as may be present on the above-described sub-ligands Lact and/or L, but also on the bivalent arylene or heteroarylene group in the structure of the formula (16), i.e. in the structure of the 5 formula (17). In a further embodiment of the emitter, the metal complex contains two R substituents or two R1 substituents which are bonded to adjacent carbon atoms and together form an aliphatic ring according to one of the formulae described 10 hereinafter. In this case, the two R substituents which form this aliphatic ring may be present on the bridge of the formula (16) and/or on one or more of the bidentate sub-ligands. The aliphatic ring which is formed by the ring formation by two R substituents together or by two R1 substituents together is preferably described by one of the following formulae (30) to (36): 15 20 25
, where R1 and R2 have the definitions given above, the dotted bonds signify the attachment of the two carbon atoms in the ligand, and in addition: 30 G is an alkylene group which has 1, 2 or 3 carbon atoms and may be substituted by one or more R2 radicals, -CR2=CR2- or an ortho-bonded arylene or heteroarylene group which has 5 or 6 aromatic ring atoms and may be substituted by one or more R2 radicals; 35
P24-194 SC R3 is the same or different at each instance and is H, F, OR2, a straight-chain alkyl group having 1 to 10 carbon atoms, a branched or cyclic alkyl group having 3 to 10 carbon atoms, where the alkyl group in each case may be substituted by one or more R2 radicals, where one or more nonadjacent CH2 groups may be replaced by R2C=CR2, C≡C, Si(R2)2, C=O, NR2, O, S or CONR2, or an aryl or heteroaryl 5 group which has 5 or 6 aromatic ring atoms and may be substituted in each case by one or more R2 radicals; at the same time, two R3 radicals which are bonded to the same carbon atom may together form an aliphatic ring system and thus form a spiro system; in addition, R3 with an adjacent R or R1 radical may form an aliphatic ring system. 10 In the above-depicted structures of the formulae (30) to (36) and the further embodiments of these structures specified as preferred, a double bond is depicted in a formal sense between the two carbon atoms. This is a simplification of the chemical structure when these two carbon atoms are incorporated into an aromatic 15 or heteroaromatic system and hence the bond between these two carbon atoms is formally between the bonding level of a single bond and that of a double bond. Preferred embodiments of the groups of the formulae (30) to (36) can be found in patent applications WO 2014/023377, WO 2015/104045 and WO 2015/117718. 20 When R radicals are bonded within the bidentate ligands or sub-ligands Lact or L or within the bivalent arylene or heteroarylene groups of the formula (17) bonded within the formula (16) or the preferred embodiments, these R radicals are the same or different at each instance and are preferably selected from the group consisting of 25 H, D, F, Br, I, N(R1)2, CN, Si(R1)3, B(OR1)2, C(=O)R1, a straight-chain alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms, where the alkyl or alkenyl group may be substituted in each case by one or more R1 radicals, or a phenyl group which may be substituted by one or more nonaromatic R1 radicals, or 30 a heteroaryl group which has 5 or 6 aromatic ring atoms and may be substituted by one or more nonaromatic R1 radicals; at the same time, two adjacent R radicals together or R together with R1 may also form a mono- or polycyclic, aliphatic or aromatic ring system. More preferably, these R radicals are the same or different at each instance and are selected from the group consisting of H, D, F, N(R1)2, a 35 straight-chain alkyl group having 1 to 6 carbon atoms or a branched or cyclic alkyl
P24-194 SC group having 3 to 10 carbon atoms, where one or more hydrogen atoms may be replaced by D or F, or a phenyl group which may be substituted by one or more nonaromatic R1 radicals, or a heteroaryl group which has 6 aromatic ring atoms and may be substituted by one or more nonaromatic R1 radicals; at the same time, two adjacent R radicals together or R together with R1 may also form a mono- or 5 polycyclic, aliphatic or aromatic ring system. Preferred R1 radicals bonded to R are the same or different at each instance and are H, D, F, N(R2)2, CN, a straight-chain alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms or a branched or cyclic alkyl group 10 having 3 to 10 carbon atoms, where the alkyl group may be substituted in each case by one or more R2 radicals, or a phenyl group which may be substituted by one or more R2 radicals, or a heteroaryl group which has 5 or 6 aromatic ring atoms and may be substituted by one or more R2 radicals; at the same time, two or more adjacent R1 radicals together may form a mono- or polycyclic aliphatic ring system. 15 Particularly preferred R1 radicals bonded to R are the same or different at each instance and are H, F, CN, a straight-chain alkyl group having 1 to 5 carbon atoms or a branched or cyclic alkyl group having 3 to 5 carbon atoms, each of which may be substituted by one or more R2 radicals, or a phenyl group which may be substituted by one or more R2 radicals, or a heteroaryl group which has 5 or 6 20 aromatic ring atoms and may be substituted by one or more R2 radicals; at the same time, two or more adjacent R1 radicals together may form a mono- or polycyclic aliphatic ring system. Preferred R2 radicals are the same or different at each instance and are H, F or an 25 aliphatic hydrocarbyl radical having 1 to 5 carbon atoms or an aromatic hydrocarbyl radical having 6 to 12 carbon atoms; at the same time, two or more R2 substituents together may also form a mono- or polycyclic aliphatic ring system. The iridium complexes are chiral structures. Both the tripodal complexes and the 30 heteroleptic complexes of bidentate sub-ligands of the IrL2L´ or IrLL´L´´ type have C1 symmetry. If the tripodal ligand of the complexes is additionally also chiral or bears three different sub-ligands (analogously in the case of the heteroleptic complexes with three different sub-ligands, i.e. of the IrLL´L´´ type), the formation of diastereomers and multiple pairs of enantiomers is possible. In that case, the 35
P24-194 SC emitters include both the mixtures of the different diastereomers or the corresponding racemates and the individual isolated diastereomers or enantiomers. Examples of suitable emitters for the emitting layer having an emission maximum wavelength ʎBGY from 450 to 585 nm are the emitters depicted in the table below: 5 10 15 20 25 30
35
P24-194 SC 5 10 15 20 25 30
35
P24-194 SC As described above, the emitting layer comprises a host system, with at least two host materials, wherein one host material is a hole-transporting host material h- TMM, and the other host material is an electron-transporting host material e-TMM. An electron-transporting host e-TMM in the context of the present invention is a 5 compound having a LUMO ≤ -2.35 eV. Preferably, the LUMO is ≤ -2.50 eV. The LUMO is the lowest unoccupied molecular orbital. The value of the LUMO of the compound is determined by cyclic voltammetry, as described in the examples section. 10 A hole-transporting host h-TMM in the context of the present invention is a compound having a HOMO ≥ -5.5 eV. The HOMO is preferably ≥ -5.4 eV. The HOMO is the highest occupied molecular orbital. The value of the HOMO of the compound is determined by cyclic voltammetry, as described in the examples section. 15 The electron-transporting host e-TMM is preferably selected from the substance classes of the triazines and the pyrimidines, more preferably from the triazines and pyrimidines of the following formula (A): 20 25
formula (A), where the symbols and indices used in formula (A) are as follows: 30 X stands on each occurrence, identically or differently, for N or CR6, preferably for N; L2 is the same or different at each instance and is a single bond or an aromatic or heteroaromatic ring system which has 5 to 24 ring atoms and may be substituted in each case by one or more R7 radicals; 35
P24-194 SC R6 at each instance is the same or different and is D, F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R7 radicals and where one or more nonadjacent 5 CH2 groups may be replaced by Si(R7)2, C=O, NR7, O, S or CONR7, or an aromatic or heteroaromatic ring system which has 5 to 60 ring atoms and which may be partially or fully deuterated in each case; it is also possible here for two R6 radicals together to form an aromatic, heteroaromatic, aliphatic, or heteroaliphatic ring system; 10 Ar5 is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted by one or more R7 radicals; R7 is the same or different at each instance and is D, F, Cl, Br, I, N(R8)2, CN, NO2, OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, 15 OSO2R8, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R8 radicals and where one or more nonadjacent CH2 groups may be replaced by Si(R8)2, C=O, NR8, O, S or 20 CONR8, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and which may be partially or fully deuterated in each case; at the same time, two or more R7 radicals together may form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system; R8 is the same or different at each instance and is H, D, F or an aliphatic, aromatic 25 or heteroaromatic organic radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F. Preferred compounds of the formula (A) are the compounds of the formulae (Aa), 30 (Ab), (Ac), (Ad), (Ae), (Af) and (Ag), 35
P24194 SC
P24194 SC
P24-194 SC 5
formula (Ag), 10 where the symbols and indices for these formulae are defined as follows: W, W1 are the same or different at each instance and are O, S, C(RW)2 or N- Ar5; 15 RW is the same or different at each instance and is a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where one or more hydrogen atoms may be replaced by D, F or CN, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted by one or more substituents selected from D, F, CN, a 20 straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where one or more hydrogen atoms in the alkyl group on the aromatic or heteroaromatic ring system may be replaced by D, F or CN; at the same time, the two RW radicals that bind to the same carbon atom may also form a ring system with one another; 25 R## is the same or different instance and is D, F, CN or an aromatic ring system which has 6 to 24 ring atoms and may be substituted by one or more R6 radicals, and two adjacent substituents R## together may form an aromatic, heteroaromatic, aliphatic, heteroaliphatic ring system that may be substituted by one or more R7 radicals; 30 A is the same or different at each instance and is CR7 or N, where not more than two A groups per cycle are N and where A is C when L2 is bonded to that position; a3 is the same or different at each instance and is 0, 1, 2, 3 or 4; 35
P24-194 SC L3 is an aromatic ring system having 6 to 40 ring atoms or a heteroaromatic ring system having 5 to 40 ring atoms, which may be substituted by one or more R7 radicals; and where L2, X, Ar5 and R7 have the definitions given above. 5 In compounds of formulae (Af), and (Ag), two X are preferably N and two X are preferably CR6 where is excluded that two adjacent X are both N. In compounds of the formula (Aa), W is preferably O or N-Ar5. 10 In compounds of the formula (Aa), A is preferably the same or different at each instance and is CR7, where A is C when L2 is bonded to that position. Preferred compounds of the formula (Aa) are the compounds of the formulae (Aa-1) to (Aa-5) 15 20 25 30
35
P24-194 SC 5 10 15 20 25
where the symbols and indices for these formulae are defined as follows: 30 Ar* is the same or different at each instance and is an aromatic ring system which has 6 to 40 ring atoms and may be substituted by one or more R7 radicals L5 is a single bond or an aromatic ring system which has 6 to 40 ring atoms and may be substituted in each case by one or more R7 radicals; (R7)x, (R7)y, (R7)x1, (R7)y1, (R7)z represent a monosubstitution, a disubstitution, a 35 trisubstitution, or the maximum permissible substitution with the radical R7,
P24-194 SC where L2, Ar5 and R7 have a previously mentioned or a previously and subsequently preferred definition. In compounds of the formulae (Aa-1), (Aa-2), (Aa-3), (Aa-4) and (Aa-5), the radicals R7 in (R7)x, (R7)y, (R7)x1, (R7)y1, (R7)z are preferably as indicated below when they 5 occur, most preferably D. In compounds of formulae (Aa), (Ab), (Ac), (Ad), (Ae), (Aa-1), (Aa-2), (Aa-3), (Aa-4) and (Aa-5), all X are preferably N. 10 Preferred compounds of the formula (Ab) are the compounds of the formula (Ab-1), 15 20
formula (Ab-1), where Ar5, L2, R##, a3, X, (R7)x, (R7)y and (R7)x1 have a meaning as described before. 25 Preferred compounds of the formula (Ac) are the compounds of the formula (Ac-1), 30 35
formula (Ac-1),
P24-194 SC where Ar5, L2, R##, a3, X, (R7)x, (R7)y and (R7)x1 have a meaning as described before. Preferred compounds of the formula (Ad) are the compounds of the formula (Ad-1), 5 10
formula (Ad-1), 15 where the symbols and indices for these formulae are defined as follows: (R7)x, (R7)y, represent a monosubstitution, a disubstitution, a trisubstitution or the maximum permissible substitution with the radical R7, where L2, X, Ar5 and R7 have a previously mentioned or a previously and 20 subsequently preferred definition. In compounds of formulae (Ab-1), (Ac-1), and (Ad-1), all X are preferably N. In a preferred embodiment of the compounds of the formulae (A), (Aa), (Ab), (Ac), 25 (Ad), (Ae), (Af), (Ag), (Aa-1), (Aa-2), (Aa-3), (Aa-4), (Aa-5), (Ab-1), (Ac-1) and (Ad-1) R7 is the same or different at each instance and is selected from the group consisting of D, F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, or an aromatic heteroaromatic ring system which has 5 to 40 ring atoms, and which may be 30 partially or fully deuterated in each case. In a particularly preferred embodiment of the compounds of the formulae (A), (Aa), (Ab), (Ac), (Ad), (Ae), (Af), (Ag), (Aa-1), (Aa-2), (Aa-3), (Aa-4), (Aa-5), (Ab-1), (Ac-1) and (Ad-1), R7 is the same or different at each instance and is selected from the 35
P24-194 SC group consisting of D or an aromatic or heteroaromatic ring system which has 6 to 30 ring atoms and which may be partially or fully deuterated in each case. The preparation of the compounds of the formulae (A), (Aa), (Ab), (Ac), (Ad), (Ae), (Af), (Ag), (Aa-1), (Aa-2), (Aa-3), (Aa-4), (Aa-5), (Aa-1), (Aa-2), (Aa-3), (Aa-4), (Aa- 5 5), (Ab-1), (Ac-1) and (Ad-1) is generally known, and some of the compounds are commercially available. If the at least one electron-transporting matrix material is a deuterated compound, it is possible that this at least one electron-transporting matrix material is a mixture of 10 deuterated compounds of the same basic chemical structure, which differ only in the degree of deuteration and/or the deuteration pattern. In a preferred embodiment of the electron-transporting matrix material, the latter is a mixture of deuterated compounds of the formulae (A), (Aa), (Ab), (Ac), (Ad), (Ae), 15 (Af), (Ag), (Aa-1), (Aa-2), (Aa-3), (Aa-4), (Aa-5), (Ab-1), (Ac-1), and (Ad-1), as described above, wherein the average deuteration level of these compounds is at least 10 mol% to 100 mol%, preferably 50 mol% to 95 mol%, more preferably 70 mol% to 90 mol%. 20 Suitable compounds of the formula (A) are known, for example, from the following publications: WO2007/077810A1, WO2008/056746A1, WO2010/136109A1, WO2011/057706A2, WO2011/160757A1, WO2012/023947A1, WO2012/048781A1, WO2013/077352A1, WO2013147205A1, WO2013/083216A1, WO2014/094963A1, WO2014/007564A1, WO2014/015931A1, WO2015/090504A2, WO2015/105251A1, 25 WO2015/169412A1, WO2016/015810A1, WO2016/013875A1, WO2016/010402A1, WO2016/033167A1, WO2017/178311A1, WO2017/076485A1, WO2017/186760A1, WO2018/004096A1, WO2018/016742A1, WO2018/123783A1, WO2018/159964A1, WO2018/174678A1, WO2018/174679A1, WO2018/174681A1, WO2018/174682A1, WO2019/177407A1, WO2019/245164A1, WO2019/240473A1, WO2019/017730A1, 30 WO2019/017731A1, WO2019/017734A1, WO2019/145316A1, WO2019/121458A1, WO2020/130381A1, WO2020/130509A1, WO2020/169241A1, WO2020/141949A1, WO2021/066623A1, WO2021/101220A1, WO2021/037401A1, WO2021/180614A1, WO2021/239772A1, WO2022/015084A1, WO2022/025714A1, WO2022/055169A1, EP3575296A1, EP3591728A1, US2014/0361254A1, US2014/0361268A1, 35
P24-194 SC KR20210036304A, KR20210036857A, KR2021147993A, JP2011/160367A2 and JP2017/107992A2. Particularly suitable compounds of formula (A) are compounds of WO2015/169412A1, described on pages 28 to 63, 93 and 110 to 114, compounds 5 of WO2019/007866A1, described in tables 1 to 8 on pages 37 to 100, compounds of WO2019/096717A2, described in table 1 on pages 27 to 33 and compounds described on pages 96 to 102, compounds of WO2019/229011A1, described in tables 1 and 2 on pages 31 to 117 and compound described on pages 251 to 254, compounds of WO2021/037401 A1, described on pages 31 to 64 and compounds 10 P1 to P110 on pages 132 to 144, compounds of WO2020/169241 A1, described in table 1 on pages 30 to 73 and compounds 1 to 36 and 67 to 81 on pages 74 to 78 and compounds described on pages 223 to 231, compounds of WO2023247662 A1, described in tables 1 and 2 on pages 18 to 23 and compounds described on pages 100 to 102, compounds of WO2023247663 A1, described in tables 1 and 2 on 15 pages 43 to 58 and compounds described on pages 151 to 173, compounds of US2023172065 A, described on pages 6 to 413 and 435 to 498, compounds of WO2016/015810 A1, described on pages 27 to 34, 51 to 56 and 61 to 64, compounds of WO18174678 A1, described on pages 20 to 32 and 38 to 50, compounds of WO18174681 A1, described on pages 20 to 32 and 42 to 61, 20 compounds of WO2021/052921 A1, described in table 1 on pages 20 to 27, compounds 1 to 11 and 29 to 44 on pages 27 to 31 and compounds described on pages 122 to 125, compounds of WO2017/178311 A1, described on pages 37 to 44 and compounds described on pages 97 to 105, compounds of WO2010/136109 A1, described on pages 32 to and compounds described in examples 1 to 54 on pages 25 74 to 139, compounds of WO2011/000455 A1, described on pages 19 to 32 and compounds described in examples 1 to 7a on pages 51 to 59, compounds of WO2021/239772 A1, described in table 1 on pages 27 to 120 and compounds E55 to E60 on pages 223 to 224 and E61 described on page 227. 30 Similarly to emitters the SCD of the hosts comes from the orientation of the electrical dipole moment of the host during the evaporation process as explained in Nature Materials, VOL 21, July 2022, 819 to 825. Hole-transporting hosts h-TMM are preferably selected from the group consisting of 35 the carbazole and triarylamine derivatives, especially the biscarbazoles, the
P24-194 SC indolocarbazoles, the bridged carbazoles, the triarylamines, the dibenzofuran- carbazole derivatives or dibenzofuran-amine derivatives, and the carbazoleamines. The hole-transporting host material h-TMM is preferably selected from the biscarbazoles, the bridged carbazoles, the triarylamines, the dibenzofuran-carbazole 5 derivatives, the dibenzofuran-amine derivatives, and the carbazoleamines of the following formulae (HH-1), (HH-2), (HH-3), (HH-4), (HH-5) and (HH-6): 10 15 20 25
o ua - ) 30 35
P24-194 SC 5 10 15 20
- , 25 where the symbols and indices used in formulae (HH-1) to (HH-6) are as follows: A1 is C(R7)2, NR7, O or S; L is a bond, O, S, C(R7)2 or NR7; A at each instance is independently a group of the formula (HH-4-1) or (HH-4- 2), 30 35
P24-194 SC 5
10 is the same or different at each instance and is CH, CR6 or N, where not more than 2 symbols X2 can be N; * indicates the binding site to the formula (HH-4); U1, U2 where they occur are a bond, O, S, C(R7)2 or NR7; R6 at each instance is the same or different and is D, F, CN, a straight-chain 15 alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group made in each case be substituted by one or more R7 radicals and where one or more nonadjacent CH2 groups may be replaced by Si(R7)2, C=O, NR7, O, S or 20 CONR7, or an aromatic or heteroaromatic ring system which has 5 to 60 ring atoms and may be substituted in each case by one or more R7 radicals; it is also possible here for two R6 radicals together to form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system; Ar5 is the same or different at each instance and is independently an aromatic 25 or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted by one or more R7 radicals; R7 is the same or different at each instance and is D, F, Cl, Br, I, N(R8)2, CN, NO2, OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, OSO2R8, a straight-chain alkyl group having 1 to 20 carbon 30 atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R8 radicals and where one or more nonadjacent CH2 groups may be replaced by Si(R8)2, C=O, NR8, O, S or CONR8, or an aromatic or 35 heteroaromatic ring system which has 5 to 40 ring atoms and may be
P24-194 SC substituted in each case by one or more R8 radicals where the R8 radical is not H; at the same time, two or more R7 radicals together may form an aromatic, heteroaromatic, aliphatic or heteroaromatic ring system; preferably, the R7 radicals do not form any such ring system; R8 is the same or different at each instance and is H, D, F or an aliphatic, 5 aromatic or heteroaromatic organic radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F; c, c1, c2 at each instance are each independently 0 or 1, where the sum total of the indices at each instance c+c1+c2 = 1; 10 d, d1, d2 at each instance are each independently 0 or 1, where the sum total of the indices at each instance d+d1+d2 = 1; q, q1, q2 at each instance is independently 0, 1, 2, 3 or 4; s is the same or different at each instance and is 0, 1, 2, 3 or 4; t is the same or different at each instance and is 0, 1, 2 or 3; 15 u is the same or different at each instance and is 0, 1 or 2; u1, u2 at each instance are each independently 0 or 1, where the sum total u1 + u2 = 1; and v is 0, 1, 2 or 3. 20 Preferred compounds of formula (HH-5) are compounds of formulae (HH-5-A) to (HH-5-E), 25
30 Formula (HH-5-A) 35
P24-194 SC 5 10 15 20 25
30 Formula (HH-5-E) where Ar5, R6, s and u have a meaning as described before or preferably described before. 35
P24-194 SC In compounds of the formulae (HH-1), (HH-2), (HH-3), (HH-5), HH-5-A), (HH-5-B), (HH-5-C), (HH-5-D), (HH-5-E) or (HH-6), s is preferably 0 or 1 when the R6 radical is not D, or more preferably 0. In compounds of the formulae (HH-1), (HH-2) or (HH-3), t is preferably 0 or 1 when 5 the R6 radical is not D, or more preferably 0. In compounds of the formulae (HH-1), (HH-2), (HH-3), (HH-5), HH-5-A), (HH-5-B), (HH-5-C), (HH-5-D) or (HH-5-E), u is preferably 0 or 1 when the R6 radical is not D, or more preferably 0. 10 The sum total of the indices s, t and u in compounds of the formulae (HH-1), (HH-2), (HH-3), (HH-5), HH-5-A), (HH-5-B), (HH-5-C), (HH-5-D), (HH-5-E) or (HH-6) is preferably not more than 6, especially preferably not more than 4 and more preferably not more than 2. This is preferably the case when R6 is not D. 15 In compounds of the formula (HH-4), c, c1, c2 at each instance are each independently 0 or 1, where the sum total of the indices at each instance c+c1+c2 is 1. c2 is preferably defined as 1. 20 In compounds of the formula (HH-4), L is preferably a single bond or C(R7)2 where R7 has a definition given above; more preferably, L is a single bond. In formula (HH-4-1), v is preferably 0 or 1 when the R6 radical is not D. In formula (HH-4-2), U1 or U2 where they occur are preferably a single bond or C(R7)2 where R7 as a definition given above; more preferably, U1 or U2 where they 25 occur are a single bond. In formula (HH-4-2), q, q1, q2 are preferably 0 or 1 when the R6 radical is not D. In a preferred embodiment of the compounds of the formulae (HH-1), (HH-2), (HH- 30 3), (HH-4), (HH-5), HH-5-A), (HH-5-B), (HH-5-C), (HH-5-D), (HH-5-E) or (HH-6), R6 is the same or different at each instance and is selected from the group consisting of D, F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl group may in each case be substituted by one or more R7 radicals, or an aromatic heteroaromatic ring 35
P24-194 SC system which has 5 to 60 ring atoms, preferably 5 to 40 ring atoms, and may be substituted in each case by one or more R7 radicals. In a preferred embodiment of the compounds of the formulae (HH-1), (HH-2), (HH- 3), (HH-4), (HH-5), HH-5-A), (HH-5-B), (HH-5-C), (HH-5-D), (HH-5-E) or (HH-6), R6 5 is the same or different at each instance and is selected from the group consisting of D or an aromatic heteroaromatic ring system which has 6 to 30 ring atoms and may be substituted by one or more R7 radicals. Preferably, Ar5 in compounds of the formulae (HH-1), (HH-2), (HH-3), (HH-5), HH-5- 10 A), (HH-5-B), (HH-5-C), (HH-5-D), (HH-5-E) or (HH-6) is selected from phenyl, biphenyl, especially ortho-, meta- or para-biphenyl, terphenyl, especially ortho-, meta- or para-terphenyl or branched terphenyl, quaterphenyl, especially ortho-, meta- or para-quaterphenyl or branched quaterphenyl, fluorenyl which may be joined via the 1, 2, 3 or 4 position, spirobifluorenyl which may be joined via the 1, 2, 15 3 or 4 position, naphthyl, especially 1- or 2-bonded naphthyl, or radicals derived from indole, benzofuran, benzothiophene, carbazole which may be joined via the 1, 2, 3 or 4 position, dibenzofuran which may be joined via the 1, 2, 3 or 4 position, dibenzothiophene which may be joined via the 1, 2, 3 or 4 position, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, 20 triazine, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene or triphenylene, each of which may be substituted by one or more R7 radicals. Ar5 is preferably deuterated, but not further substituted. When A1 in formula (HH-2) or (HH-3) or (HH-6) is NR7, the substituent R7 bonded to 25 the nitrogen atom is preferably an aromatic or heteroaromatic ring system which has 5 to 24 ring atoms and may also be substituted by one or more R8 radicals. In a particularly preferred embodiment, this substituent R7 is the same or different at each instance and is an aromatic or heteroaromatic ring system having 6 to 24 ring atoms, especially having 6 to 18 ring atoms. Preferred embodiments of R7 are 30 phenyl, biphenyl, terphenyl and quaterphenyl, which are preferably unsubstituted, and radicals derived from triazine, pyrimidine and quinazoline, which may be substituted by one or more R8 radicals where the R8 radical is not H. When A1 in formula (HH-2) or (HH-3) or (HH-6) is C(R7)2, the substituents R7 35 bonded to this carbon atom are preferably the same or different at each instance
P24-194 SC and are a linear alkyl group having 1 to 10 carbon atoms or a branched or cyclic alkyl group having 3 to 10 carbon atoms or an aromatic or heteroaromatic ring system having 5 to 24 ring atoms, which may also be substituted by one or more R8 radicals where the R8 radical is not H. Most preferably, R7 is a methyl group or a phenyl group. In this case, the R7 radicals together may also form a ring system, 5 which leads to a spiro system. In a preferred embodiment of the compounds of the formulae (HH-1), (HH-2), (HH- 3), (HH-4), (HH-5), (HH-5-A), (HH-5-B), (HH-5-C), (HH-5-D), (HH-5-E) and (HH-6), these compounds are partly or fully deuterated, more preferably fully deuterated. 10 The preparation of the compounds of the formulae (HH-1), (HH-2), (HH-3), (HH-4), (HH-5), (HH-5-A), (HH-5-B), (HH-5-C), (HH-5-D), (HH-5-E) and (HH-6) is generally known, and some of the compounds are commercially available. 15 Compounds of the formula (HH-4) are disclosed, for example, in WO2021/180614, pages 110 to 119, especially as examples on pages 120 to 127. The preparation thereof is disclosed in WO2021/180614 A1 on page 128, and in the synthesis examples on pages 214 to 218. 20 The preparation of the triarylamines of the formula (HH-6) is known to the person skilled in the art, and some of the compounds are commercially available. If the at least one hole-transporting matrix material h-TMM is a deuterated compound, it is possible that this at least one hole-transporting matrix material is a 25 mixture of deuterated compounds of the same basic chemical structure, which differ only in the degree of deuteration and/or the deuteration pattern. In a preferred embodiment of the at least one hole-transporting matrix material h- TMM, this is a mixture of deuterated compounds of the formulae (HH-1), (HH-2), 30 (HH-3), (HH-4), (HH-5), (HH-5-A), (HH-5-B), (HH-5-C), (HH-5-D), (HH-5-E) or (HH- 6), as described above, wherein the average deuteration level of these compounds is at least 50 mol% to 90 mol%, preferably 70 mol% to 100 mol%. Examples of suitable hole-transporting matrix materials h-TMM for a combination 35 with compounds of the formula (A), as described above or described as preferred,
P24-194 SC are the compounds described in WO2019/229011 A1, table 3, pages 137 to 203, which may also be partly or fully deuterated. Examples of suitable hole-transporting matrix materials h-TMM for a combination with compounds of the formula (A) or preferred compounds of the formula (A), as 5 described above or described as preferred, are the compounds described in WO2021/180625 A1, table 3, pages 131 to 137, and in table 4, pages 137 to 139, which may also be partly or fully deuterated. Examples of suitable hole-transporting matrix materials h-TMM for a combination 10 with compounds of the formula (A) or preferred compounds of the formula (A), as described above or described as preferred, are the compounds described in WO2011/088877 A1, table on page 30, compounds 1 to 166, which may also be partly or fully deuterated. 15 Examples of suitable hole-transporting matrix materials h-TMM for a combination with compounds of the formula (A) or preferred compounds of the formula (A), as described above or described as preferred, are the compounds described in WO2011/128017 A1, table on page 23, compounds 1 to 151, which may also be partly or fully deuterated. 20 Examples of suitable hole-transporting matrix materials h-TMM for a combination with compounds of the formula (A) or preferred compounds of the formula (A), as described above or described as preferred, are the compounds described in KR20230034896 A, on pages 42 to 47, compounds [2-1] to [2-110], or on pages 49 25 to 51, compounds [3-1] to [3-26]. Examples of suitable hole-transporting matrix materials h-TMM for a combination with compounds of the formula (A) or preferred compounds of the formula (A), as described above or described as preferred, are the compounds described in 30 KR20230154750 A, on pages 39 to 49, compounds [B-1] to [B-243], or on pages 49 to 53, compounds [C-1] to [C-102], or on pages 54 to 57, compounds [D-1] bis [D- 120]. Examples of suitable hole-transporting matrix materials h-TMM for a combination 35 with compounds of formula (A) or preferred compounds of formula (A), as previously
P24-194 SC described or preferably described, are the compounds described in US 2023/172065 A, on pages 413 to 434. For a combination with compounds of the formulae (A), (Aa), (Ab), (Ac), (Ad), (Ae), (Af) or (Ag), as described above or described with preference, especially suitable 5 compounds are those of the formula (HH-1) and/or of the formula (HH-4) and/or of the formulae (HH-5), (HH-5-A), (HH-5-B), (HH-5-C), (HH-5-D) and (HH-5-E), as described above or described as preferred. In the subgroup of compounds of the formula (HH-5), selected from compounds of the formulae (HH-5-A), (HH-5-B), (HH- 5-C), (HH-5-D), (HH-5-E), compounds of the formulae (HH-5-A, (HH-5-B) and (HH- 10 5-D) are preferred; compounds of the formula (HH-5-A) being particularly preferred. For a combination with compounds of the formulae (A), (Aa), (Ab), (Ac), (Ad), (Ae), (Af) or (Ag), as described above or described with preference, especially suitable compounds are those of the formulae (HH-1), (HH-4) and/or (HH-5). 15 For a combination with a compound of the formulae (A), (Aa), (Ab), (Ac), (Ad), (Ae), (Af) or (Ag), as described above or described with preference, very particular preference is given to compounds of the formula (HH-4) or (HH-5) or (HH-5-A).] 20 Host systems comprising a hole-transporting host and an electron-transporting host are described, for example, in WO 2019/158453, WO 2019/007866, WO 2019/007867, WO 2019/229011 and WO 2021/037401. The present invention accordingly further provides an organic light emitting device 25 comprising an anode, a cathode and at least one light emitting layer arranged between the anode and the cathode, wherein the at least one light emitting layer comprises beside at least one emitter a host system comprising at least two host materials, wherein the first host material is a hole-transporting host material h-TMM, preferably selected from the compounds of formulae (HH-1), (HH-2), (HH-3), (HH-4), 30 (HH-5), and (HH-6), more preferably selected from the compounds of formulae (HH- 5-A), (HH-5-B), (HH-5C), (HH-5D), and (HH-5E), and the second host material is an electron-transporting host material e-TMM, preferably selected from the compounds of formula (A), more preferably selected from the compounds of formulae (Aa), (Ab), (Ac), (Ad), (Ae), (Af), and (Ag), characterized in that the surface charge density of 35
P24-194 SC the host system SCDhost is greater than 0.5 mC/m2 or is as preferably described herein. The organic light emitting device comprises cathode, anode and at least one light emitting layer. Apart from these layers, it may comprise still further layers, for 5 example in each case, one or more hole injection layers, hole transport layers, hole blocker layers, electron transport layers, electron injection layers, exciton blocker layers, electron blocker layers, charge generation layers and/or organic or inorganic p/n junctions. In this case, it is possible that one or more hole transport layers are p- doped, for example with metal oxides such as MoO3 or WO3, or with (per)fluorinated 10 electron-deficient aromatics or with electron-deficient cyano-substituted heteroaromatics (for example according to JP 4747558, JP 2006-135145, US 2006/0289882, WO 2012/095143), or with quinoid systems (for example according to EP1336208) or with Lewis acids, or with boranes (for example according to US 2003/0006411, WO 2002/051850, WO 2015/049030) or with carboxylates of the 15 elements of main group 3, 4 or 5 (WO 2015/018539), and/or that one or more electron transport layers are n-doped. It is likewise possible for interlayers to be introduced between two light emitting layers, which have, for example, an exciton-blocking function and/or control charge 20 balance in the electroluminescent device and/or generate charges (charge generation layer, for example in layer systems having two or more light emitting layers, for example in white OLEDs). However, it should be pointed out, that each of these layers does not necessarily have to be present. 25 In this case, it is possible for the organic light emitting device to contain a light emitting layer, or for it to contain a plurality of light emitting layers. If a plurality of emission layers is present, these preferably have several emission maxima between 380 nm and 750 nm overall, such that the overall result is white emission; in other words, various emitting compounds which may fluoresce or phosphoresce are used 30 in the light emitting layers. Especially preferred are three-layer systems where the three layers exhibit blue, green, and orange or red emission (for the basic construction see, for example, WO 2005/011013), or systems having more than three light emitting layers. The system may also be a hybrid system wherein one or more layers fluoresce, and one or more other layers phosphoresce. Another 35 embodiment are tandem OLEDs. A tandem OLED is an OLED that has two or more
P24-194 SC electroluminescence (EL) units connected electrically in series with unique intermediate connectors within the device. White-emitting organic electroluminescent devices may be used for lighting applications or else with colour filters for full-colour displays. 5 The light emitting layers might also comprise a mixture of two or more triplet emitters, especially two or three triplet emitters, together with one or more host materials and/or with the host system having the surface charge density SCDhost which is greater than 0.5 mC/m2. In this case of two or three triplet emitters, the triplet emitter having the shorter-wave emission spectrum serves as co-host for the 10 triplet emitter having the longer-wave emission spectrum. A preferred embodiment in the case of use of a mixture of three triplet emitters is when two are used as co- host and one as emitting material. These triplet emitters preferably have the emission colours of green, yellow, and red, or blue, green, and orange. 15 Preferred cathodes are metals having a low work function, metal alloys or multilayer structures composed of various metals, for example alkaline earth metals, alkali metals, main group metals or lanthanoids (e.g.: Ca, Ba, Mg, Al, In, Yb, Sm, etc.). Additionally suitable are alloys composed of an alkali metal or alkaline earth metal and silver, for example an alloy composed of magnesium and silver. In the case of 20 multilayer structures, in addition to the metals mentioned, it is also possible to use further metals having a relatively high work function, for example Ag, in which case combinations of the metals such as Mg/Ag, Ca/Ag or Ba/Ag, for example, are generally used. It may also be preferable to introduce a thin interlayer of a material having a high dielectric constant between a metallic cathode and the organic 25 semiconductor. Examples of useful materials for this purpose are alkali metal or alkaline earth metal fluorides, but also the corresponding oxides or carbonates (e.g.: LiF, Li2O, BaF2, MgO, NaF, CsF, Cs2CO3, etc.). Likewise useful for this purpose are organic alkali metal complexes, e.g.: Liq (lithium quinolinate). The layer thickness of this layer is preferably between 0.5 and 5 nm. 30 Preferred anodes are materials having a high work function. Preferably, the anode has a work function of greater than 4.5 eV versus vacuum. Firstly, metals having a high redox potential are suitable for this purpose, for example Ag, Pt or Au. Secondly, metal/metal oxide electrodes (e.g.: Al/Ni/NiOx, Al/PtOx) may also be 35 preferred. For some applications, at least one of the electrodes has to be
P24-194 SC transparent or partly transparent in order to enable either the irradiation of the organic material (O-SC) or the emission of light (OLED/PLED, O-LASER). Preferred anode materials here are conductive mixed metal oxides. Particular preference is given to indium tin oxide (ITO) or indium zinc oxide (IZO). Preference is further given to conductive doped organic materials, especially conductive doped polymers, for 5 example PEDOT, PANI or derivatives of these polymers. It is further preferable when a p-doped hole transport material is applied to the anode as hole injection layer, in which case suitable p-dopants are metal oxides, for example MoO3 or WO3, or (per)fluorinated electron-deficient aromatic systems. Further suitable p-dopants are HAT-CN (hexacyanohexaazatriphenylene) or the compound NPD9 from 10 Novaled. Such a layer simplifies hole injection into materials having a low HOMO, i.e.: a large HOMO in terms of magnitude. In the further layers, it is generally possible to use any materials as used according to the prior art for the layers, and the person skilled in the art is able, without 15 exercising inventive skill, to combine any of these materials with the materials of the invention in an electronic device. Suitable charge transport materials as usable in the hole injection or hole transport layer or electron blocker layer or in the electron transport layer of the organic 20 electroluminescent device of the invention are, for example, the compounds disclosed in Y. Shirota et al., Chem. Rev.2007, 107(4), 953-1010, or other materials as used in these layers according to the prior art. Preferred hole transport materials which can be used in a hole transport, hole injection or electron blocker layer in the electroluminescent device of the invention are indenofluoreneamine derivatives (for 25 example according to WO 06/122630 or WO 06/100896), the amine derivatives disclosed in EP 1661888, hexaazatriphenylene derivatives (for example according to WO 01/049806), amine derivatives having fused aromatic systems (for example according to US 5,061,569), the amine derivatives disclosed in WO 95/09147, monobenzoindenofluoreneamines (for example according to WO 08/006449), 30 dibenzoindenofluoreneamines (for example according to WO 07/140847), spirobifluoreneamines (for example according to WO 2012/034627, WO 2014/056565), fluoreneamines (for example according to EP 2875092, EP 2875699 and EP 2875004), spirodibenzopyranamines (for example according to EP 2780325) and dihydroacridine derivatives (for example according to WO 35 2012/150001).
P24-194 SC The device is correspondingly (according to the application) structured, contact- connected and finally hermetically sealed since the lifetime of such devices is severely shortened in the presence of water and/or air. 5 Additionally preferred is an organic electroluminescent device, characterized in that one or more layers are coated by a sublimation process. In this case, the materials are applied by vapour deposition in vacuum sublimation systems at an initial pressure of typically less than 10-5 mbar, preferably less than 10-6 mbar. It is also possible that the initial pressure is even lower or even higher, for example less than 10 10-7 mbar. Preference is likewise given to an organic electroluminescent device, characterized in that one or more layers are coated by the OVPD (organic vapour phase deposition) method or with the aid of a carrier gas sublimation. In this case, the 15 materials are applied at a pressure between 10-5 mbar and 1 bar. A special case of this method is the OVJP (organic vapour jet printing) method, in which the materials are applied directly by a nozzle and thus structured. The organic electroluminescent device can also be produced as a hybrid system by 20 applying one or more layers from solution and applying one or more other layers by vapour deposition. For example, it is possible to apply an emitting layer comprising a metal complex of the invention and a matrix material from solution, and to apply a hole blocker layer and/or an electron transport layer thereto by vapour deposition under reduced pressure. 25 These methods are known in general terms to those skilled in the art and can be applied by those skilled in the art without any problems to organic electroluminescent devices comprising the compounds of the invention. In a preferred embodiment of the invention, the emitting layer is applied by a sublimation 30 method. The invention is illustrated in more detail by the examples which follow, without any intention of restricting it thereby. The person skilled in the art will be able to use the details given, without exercising inventive skill, to produce further electronic devices 35 of the invention and hence to execute the invention over the entire scope claimed.
P24-194 SC Description of the figures Cross-sectional view illustrating a device used for SCD (Surface Charge Density) experiments according to an embodiment of the present invention. 5 Cross-sectional view illustrating an OLED device according to an embodiment of the present invention. Examples: 10 General methods: Cyclic Voltammetry For cyclic voltammetry measurements, a potentiostat from Metronon µAUTOLAB 15 type III in a three-electrode setup is used including working-electrode (Au), counter- electrode (Pt) and reference-electrode (Ag/AgCl, KCl 3M). Oxidation is measured in methylene chloride (DCM) and reduction in Tetrahydrofuran (THF) and tetrabutylammonium hexafluorophosphate (0.11 M) is added as electrolyte. Ferrocene or decamethylferrocene are used as internal standard. 20 Determination of the triplet energy of the hosts The triplet energy of hosts is computed from quantum-chemistry using the Gaussian program package (Gaussian16). Singlet ground state geometries were optimized at the B3LYP/6-31G(d) level of theory. Subsequently, TD-DFT triplet excitation 25 energies (vertical transitions) were computed using the optimized ground state geometry and the same method (B3LYP/6-31G(d)). Default settings for SCF and geometry convergence were employed and T1 was calculated for one representative conformation. 30 Photoluminescence spectrum The photoluminescence spectrum of the emitter chosen is generally measured in oxygen-free solution, 10-5 molar, at room temperature, a suitable solvent being any 35 in which the chosen emitter dissolves in the concentration mentioned. Particularly
P24-194 SC suitable solvents are typically toluene or 2-methyl-THF, but also dichloromethane. Measurement is carried out with a commercially available photoluminescence spectrometer. The triplet energy T1 in eV is determined from the photoluminescence spectra of the emitters. Firstly, the peak maximum Plmax. (in nm) of the photoluminescence spectrum is determined. The peak maximum Plmax. (in nm) is 5 then converted to eV by: E(T1 in eV) = 1240 / E(T1 in nm) = 1240 / PLmax. (in nm). Part 1: Method of determining the Surface Charge Density (SCD) for an emitter material (as in WO 2024/170609 A1) or a host material 10 1.1 Preparation of the test devices for SCD measurements: Glass plates with structured ITO (50 nm, indium tin oxide) form the substrates on which the OLEDs are processed. Before evaporation of the materials, the substrates are cleaned in a wet process (using filtered deionized water and the detergent “Extran” of Merck KGaA). Glass substrates are then dried for 15 minutes at 170°C. 15 Subsequently the clean and dry substrates are exposed to an oxygen and subsequently to an argon plasma. The structure of the test devices used for the SCD measurements is represented in Fig.1. The anode is an ITO electrode, the HIL (Hole Injection Layer) has a thickness 20 of 10 nm and consists of a mixture of HTM1 and PD1 (95%:5%) (meaning HTM1 is present in the layer in a proportion 95 % by volume and PD1 is present in the layer in a proportion of 5 % by volume), the HTL (Hole Transport Layer) has a thickness of 100 nm and consists of HTM1, the test layer has a thickness of 40 nm and consists of the investigated material and an auxiliary host (x % by weight : (100-x) % 25 by weight) and the cathode is a 100 nm thick aluminum electrode. The symbol x represents the concentration of the investigated material in the corresponding layer. The auxiliary material is e-TMM1 in case of determination of SCD for an Emitter while the auxiliary material e-TMM2 is used in case of determination of SCD for hosts. 30 Generally, there is no limitation to the selection of the hole injection material and the hole-transporting material to be used in the test devices for SCD measurements. However, it is recommended to use an HTL with a small SCD or GSPS like for example the well-known material NPB. The material used in this invention HTM1 also has a small SCD of SCDHTL=-0.1 mC/m2 roughly equivalent to a GSPS of 35 +4mV/nm.
P24-194 SC All materials are applied by thermal vapor deposition in a vacuum chamber, preferably at an evaporation rate of 1 Å /s. The structures of the materials are depicted in Table 1 below. 5 Table 1: Auxiliary materials for the SCD measurements: 10 15 20
1.2 Determination of the build-in voltage Ubi: 25 All test devices for the SCD measurements are characterized by standard current/voltage/luminance measurements (IUL measurements) assuming a Lambertian emission profile. For the analysis of SCDs, the build-in voltage Ubi is taken from the current/voltage characteristics. 30 1.3 Dielectric spectroscopy measurements The Surface Charge Density of the investigated material is determined via dielectric spectroscopy measurements using an Alpha-NB Single-Unit Dielectric Analyzer (Novocontrol technologies) combined with a dielectric interface (Novocontrol ZGS). This setup allows frequency sweeps covering a range from 35
P24-194 SC f = 10−2 to f = 107 Hz. The AC rms voltage UAC is set to 100 mV for all measurements and the superimposed DC bias UDC is varied between -7 and 7 V. The experimental capacity C-f-UDC curves are analyzed according to the theoretical description in J. Appl. Phys.107, 1–9 (2010) for Utrans and CSCD with a fixed frequency f = 104 Hz in order to observe all necessary quantities for the final surface 5 charge density SCD of the material under test:
Here, SCDHTL is -0.1 mC/m2 as HTM1 is used at HTL. 10 As mentioned above, the build-in voltage Ubi is taken from the IUL measurements. “A” depicts the active electrode area of the OLED device. Final surface charge density for a material is calculated/extrapolated to 100% of the investigated material from a set of experiments where the concentration of the investigated material is x = 0%, 10%, 20%, 30% in case of emitters with auxiliary material e-TMM1 and is x = 15 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70% in case of hosts with auxiliary material e-TMM2. In case of a host systems comprising at least two host materials the surface charge- density of the host system SCDhost is determined according to the following formula: 20
wherein: n = 1 to N is the number of the different host materials used, 25 cn is the concentration of the different host materials in % by volume, and SCDn is the individual SCD of the layer of the individual host n obtained in concentration series with an auxiliary material and extrapolated to 100% as explained above in this section. 30 Part 2: Determination of the HOMO and LUMO energies of the materials by cyclic voltammetry For cyclic voltammetry measurements, a potentiostat from Metronon µAUTOLAB type III in a three-electrode-setup is used including working-electrode (Au), counter 35 electrode (Pt) and reference-electrode (Ag/AgCl, KCl 3M). Oxidation is measured in
P24-194 SC methylene chloride (DCM) and reduction in tetrahydrofuran (THF) and tetrabutylammonium hexafluorophosphate (0.11 M) is added as electrolyte. Ferrocene or decamethylferrocene are used as internal standard. Part 3: Fabrication of OLEDs 5 Examples E1 to E10 according to the present invention and Comparative Examples C1 to C6 according to the prior art The exact structure of the OLEDs is shown in the following Table 2 as well as in Fig. 2. 10 The materials required for the preparation of these OLEDs are shown in the following Table 3 (unless already contained in Table 1). Glass plates coated with structured ITO (indium tin oxide) in a thickness of 50 nm 15 are used as substrates for device fabrication. All materials are applied by thermal vapour deposition in a vacuum chamber. The emission layer here always consists of at least two matrix materials (host materials) and an emitting dopant (emitter), which is admixed with the matrix materials in a 20 certain proportion by volume by co-evaporation. An expression such as e-TMM3:h- TMM4:TEG1 (55%:35%:10%) here means that material e-TMM3 is present in the layer in a proportion of 55% by volume, h-TMM4 is present in the layer in a proportion of 35% by volume such that e-TMM3 and h-TMM4 together form the host system and TEG1 is present in the layer in a proportion of 10% by volume. 25 Analogously, the injection and/or transport layers may also consist of a mixture of two materials. The host impact in three different OLED stacks is investigated, which differ in terms of layer thicknesses, used EBL material (HTM1 for C1 to E4 in Table 2 vs HTM3 for 30 C4 onwards) and used emitter (TEG1 for C1 to E6 vs TEG2 for C6 onward). Emitter concentrations are always 8% and the hole-transporting host in the mixed host system is always h-TMM4 except for examples E9 and E10, where h-TMM9 is used. The OLEDs are characterised by standard methods. For this purpose, 35 electroluminescence spectra as well as current-voltage-luminance curves are
P24-194 SC measured, and the external quantum efficiency (EQE) is calculated assuming Lambertian emission characteristics. Electroluminescence spectra are determined at a luminous density of 1000 cd/m2, and the CIE 1931 x and y colour coordinates are calculated on this basis. The term U10 in Table 4 denotes the voltage required for a current density of 10 mA/cm2. Similarly, EQE10 denotes the EQE obtained at a 5 current density of 10 mA/cm2. The lifetime LT is defined as the time after which, upon operation at a constant cur- rent density, the brightness (in cd/A) drops from the initial value L0 to the reduced value L1. Thus, L1/L0 = 90% in Table 4 means that the value in the column LT corresponds to the time (in h) after which the brightness of the OLED has been 10 reduced to 90% of its initial value. The results obtained from the various OLEDs are summarised in Table 4. Table 2: Structure of the OLEDs: 15 20 25 30 35
P24-194 SC 5 10 15 20 25 30
35
P24-194 SC Table 3: Materials used in the OLED preparation: 5 10 15 20 25 30
35
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35
P24-194 SC 5 10 15 20 25 30
35
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Table 4: OLED results: 10 15 20
Part 4: Determination of the area under the capacitance-voltage curve 25 The charge (Q) or area-under-C/V for the OLEDs of Table 2 is generally calculated using the integral of the capacitance (C) beginning from the onset voltage (Vonset), the voltage point, where the capacitance curve is leaving the geometrical capacitance (Cgeo) values, up to the voltage of the capacitance maximum (Vmax): 30
However, depending on the stack composition the voltages for the capacitance 35 peaks can vary significantly and can also be much higher than the built-in-voltages
P24-194 SC (Vbi), where the current is already flowing within the device. From this point on, additional dynamic capacitance effects come into play which are superimposing the static capacitance values, and therefore, are not directly comparable to measured devices anymore where only static capacitance effects are contributing to the C/V curve. 5 Hence, area-under-C/V is not calculated up to the voltage of the capacitance maximum, but only up to the built-in-voltage, which is defined to be the voltage where a current density of 1^10-3 mA/cm² is reached within the OLED stack. By this, only the static capacitance of the OLED stack is considered which ensures the 10 comparability between the different OLED stacks. A frequency of 100 Hz is used for evaluation of the area-under-C/V using Microsoft Excel: the starting point (onset voltage) is first defined within the C/V curve by choosing the point, where the curve significantly leaves the geometrical capacitance 15 for the first time. The built-in-voltage needs to be read out the V/I curve as the voltage at which a current density of 1^10-3 mA/cm² is reached. Then, the evaluation is done using the OFFSET function to set the voltage range in which the integration of the capacitance is done using the SUM function. The Excel OFFSET function returns a reference to a range constructed with five inputs: (1) a starting point, (2) a 20 row offset, (3) a column offset, (4) a height in rows, and (5) a width in columns. Part 5: Results The SCD values and electronic properties of the materials are shown in Table 5 25 below. In Tables 6, 7 and 8 it is shown that for three different OLED stacks, varying in layer thickness, EBL material and emitter material, host systems with a more positive SCDhost lead to a lower area-under-C/V (representing the amount of charge stored 30 in this plate-capacitor). This indicates that positive host systems with SCDhost > 0.5 mC/m2 lead to faster charging and de-charging of the OLED pixel which constitutes a main advantage especially for higher display refresh-rates. Different concentrations of e-TMM3 in the mixed host system are shown in 35 Comparative Examples C1 and C2.
P24-194 SC It is also shown that different SCDs of the electron-blocking layer impact the capacitance. In Comparative Example C1 (see: Table 6) HTM1 is used with a SCDHTM1 = -0.1 mC/m2, while in Comparative Example C4 (see: Table 7) HTM3 is used with a SCDHTM3 = -0.60 mC/m2. 5 Finally, we also exchange the emitter as compared to examples in Table 7 showing again lower capacitance for host systems with SCDhost > 0.5 mC/m2 (Table 8). Table 5: SCD, HOMO, LUMO, T1 of the investigated materials: 10 15 20 25 30 35
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5 Table 6: Area-under-Capacitance-voltage curve versus surface charge density of the host system (SCDhost) for the first OLED stack: 10 15
As can be seen from Table 6, the OLEDs in the Comparative Examples C1 to C3 have host systems with only a weakly positive SCDhost (0 < SCDhost < 0.5 mC/m2) showing a high capacitance. This includes Reference Example Ref.1, with a host 20 system of e-TMM3:h-TMM5 (50%:50%) according to Example 9 of US 2021391544 A1 (C1:H-2). This host system is used together with emitter TEG3 (SCDEmitter = -1.96 mC/m2). The hole transporting host h-TMM5 of Ref.1 (H-2) is very similar in terms of 25 electronic properties to the hole transporting host h-TMM4 as used in Comparative Example C1. In CN118063377 A, a similar mixed host system is used as in Ref.1 together with the emitter TEG4 (SCDEmitter = -2.37 mC/m2). None of the disclosed mixed host 30 systems show an SCD value greater than 0.5 mC/m2. One representative host system shown in table 11 therein is a (50%:50%) mixture of H21 with XF02. H21 corresponds to h-TMM6 as described before. The material XF02 corresponds to e- TMM12 as described before. The SCD value SCDhost of said mixture is -1.69 mC/m2 which will result in a high capacitance. 35
P24-194 SC In contrast to these comparative OLEDs, the OLEDs of the present invention according to Examples E1 to E4 show a SCDhost > 0.5 mC/m2 yielding in a lower capacitance allowing for faster switching times for these OLEDs. E4 with most positive SCDhost results in lowest capacitance. 5 Next, the hole-injection layer and the electron blocking layer has been modified as indicated by “change” in Table 2. The host system used in C1 and C4 is identical. Again, Table 7 shows that a SCDhost > 0.5 mC/m2 yields a lower capacitance. Table 7: Area-under-Capacitance-voltage curve versus surface charge density of 10 the host system for the second OLED stack differing in layer thicknesses and EBL material used as compared to the first OLED stack (see: Table 6): 15
Finally, we also change the emitter as indicated by “change” in Table 2. C4 and C6 are identical except for the emitter used, which is the same for E6 and E8. As shown 20 in Table 8 again a SCDhost > 0.5 mC/m2 yields a lower capacitance and E10 with most positive SCDhost results in lowest capacitance. Table 8: Area-under-Capacitance-voltage curve versus surface charge density of the host system for the third OLED stack differing only in emitter material compared 25 to the second OLED stack (see: Table 7): 30
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