EP1716725A1

EP1716725A1 - Organic electronic devices

Info

Publication number: EP1716725A1
Application number: EP05715402A
Authority: EP
Inventors: Anja Gerhard; Horst Vestweber; Philipp STÖSSEL
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2004-02-20
Filing date: 2005-02-18
Publication date: 2006-11-02
Also published as: CN1922930A; KR101175959B1; KR20060127138A; JP2007526634A; JP2007527116A; US20070170419A1; CN100482023C; JP5253739B2; US7838126B2; WO2005084081A1; US7776455B2; WO2005084082A1; EP1716724A1; US20070164273A1; CN1922929A; KR20060133584A; DE102004008304A1

Abstract

The invention relates to the improvement of organic electronic devices, in particular, fluorescent electroluminescence devices, where electron transport materials of formula (1) to (4) are used as in scheme 1.

Description

description

Organic electronic devices

The present invention describes the novel use of certain compounds in organic electronic devices.

In a number of different applications, which can be broadly attributed to the electronics industry, the use of organic semiconductors has been a reality for some time or is expected in the near future. The use of semiconducting organic compounds that are capable of emitting light in the visible spectral range is just at the beginning of the market launch, for example in organic electroluminescent devices. The market launch for simple devices containing OLEDs has already taken place, as evidenced by the car radios from Pioneer, the mobile phones from Pioneer and SNMD and a digital camera from Kodak with an "organic display". Other such products are about to be launched. Organic solar cells (O-SCs), organic field effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic switching elements (O-ICs), organic optical amplifiers or organic laser diodes (O-lasers) are far in the research stage advanced and could become very important in the future.

The general structure of organic electroluminescent devices (OLEDs) is described, for example, in US 4,539,507, US 5,151, 629, EP 0676461, WO 98/27136 and WO 04/058911, these devices usually consisting of several layers. Organic solar cells (e.g. WO 98/48433, WO 94/05045), organic field-effect transistors (e.g. US 5705826, US 5596208, WO 00/42668), organic thin-film transistors, organic switching elements (e.g. WO 95/31833, WO 99/10939), organic optical amplifiers or organic laser diodes (e.g. WO 98/03566) have a similar general structure.

However, there are still significant problems that need urgent improvement:

1. The efficiency has been improved in recent years, but is still too low, especially in the case of fluorescent OLEDs, and must be improved.

2. The operating voltage and the operating current are quite high, especially in the case of fluorescent OLEDs, and must therefore be reduced further in order to Improve performance efficiency. This is particularly important for mobile applications.

3. The operational life of the electronic devices is still short, so that only simple applications could be realized commercially until now.

4. For many applications, thicker electron transport layers are required than can be achieved with the materials currently used, since the charge carrier mobility of these materials is insufficient.

5. The most commonly used AIQ electron conductor has several disadvantages, which are detailed below.

For many applications it would be desirable to be able to use thicker layers of an electron transport material. This would have the advantage that the occurrence of short circuits could be reduced or prevented altogether. This is especially true when a combination of fluorescent blue and phosphorescent red and green OLEDs is used in displays. Since the phosphorescent OLEDs generally have a thicker layer structure, the fluorescent blue OLED must contain a thicker electron transport layer so that the different OLEDs have the same thickness. However, since the electron mobility of the

Electron transport connections according to the prior art are not sufficient for this, this is not yet possible in practice.

Fluorescent electroluminescent devices that use AIQ ₃ as electron conductors have long been known and were described in US 4,539,507 as early as 1993; AIQ ₃ has since been used in most OLEDs

Electron transport material used. In the above application, it is used as an electron transport material in the emission layer. However, AIQ ₃ has several disadvantages: It cannot be vapor-deposited without residue, since it partially decomposes at the sublimation temperature, which is particularly true for

Production equipment is a big problem. As a result, the evaporation sources have to be cleaned or replaced again and again. Furthermore, decomposition products from AIQ _{3 get} into the OLED, which contribute to a reduced lifespan and reduced quantum and power efficiency. A major practical disadvantage is the strong hygroscopy of

AIQ ₃ . Synthesized and stored under normal conditions, in addition to the hydroxyquinoline ligands, AIQ ₃ still contains one molecule of water per complex molecule (H. Schmidbaur et al., Z. Naturforsch. 1991, 46b, 901-911), which is extremely heavy is to be removed. For use in OLEDs, AIQ ₃ must therefore be laboriously cleaned in complicated, multi-stage sublimation processes and then stored and handled in a protective gas atmosphere with the exclusion of water. Furthermore, large fluctuations in the quality of individual AIQ ₃ batches and poor storage stability were found (S. Karg, E-MRS

Conference 30.5.00-2.6.00, Strasbourg). AIQ ₃ also has low electron mobility, which leads to higher voltages and thus lower power efficiency. To avoid short circuits in the display, one would like to increase the layer thickness; this is not possible with AIQ ₃ due to the low mobility of the charge carriers and the resulting increase in voltage. The charge carrier mobility of other electron conductors (US Pat. No. 4,539,507) is also too low to build up thicker layers with it, the lifetime of the OLED being even worse than when using AIQ ₃ . The intrinsic color (yellow in solid) of AIQ ₃ also proves to be very unfavorable, which is particularly the case with blue OLEDs due to reabsorption and weak re-emission

Color shifts can result. Here, blue OLEDs can only be used with high efficiency or Loss of color space can be represented. Another disadvantage of using AIQ ₃ is the instability towards holes (Z. Popovic et al, Proceedings of SPIE 1999, 3797, 310-315), which can always lead to problems in the component during long-term use.

Despite the disadvantages mentioned, AIQ ₃ in OLEDs has so far always been the best compromise for the various requirements for an electron transport material. No satisfactory electron transport material has yet been found for the other applications mentioned.

There is therefore still a need for electron transport materials which lead to good efficiencies in organic electronic devices and at the same time lead to long lifetimes. It has now surprisingly been found that organic electronic devices which contain certain compounds - listed below - as electron transport materials clearly

Have improvements over the prior art. With these materials it is possible to obtain high efficiencies and long lifetimes at the same time, which is not possible with materials according to the prior art. In addition, it was found that the operating voltages can also be significantly reduced, which corresponds to higher power efficiencies and additionally thicker ones

Electron transport layers can be used, which reduces or prevents the frequency of short circuits and brings further advantages already mentioned above. The invention relates to an organic electronic device containing the cathode, anode and at least one organic layer, characterized in that the organic layer contains at least one defined compound A with the chemical structural unit Y = X, where the symbols used are: Y is at each occurrence the same or different P, As, Sb, Bi, S, Se or Te;

X is the same or different on each occurrence O, S, Se, Te or NR;

R is the same or different each time an organic radical having 1 to 22 carbon atoms or OH or NH ₂ ; with the proviso that the compound A has a molecular weight of> 150 g / mol and <10000 g / mol and that the device has no phosphorescent

Contains emitter; and with the proviso that the following compounds are excluded from the invention:

The symbol used above and below, "=" stands for a double bond in the sense of the Lewis notation.

For the purposes of this invention, a “defined compound” is to be understood to mean a compound which has a composition and structure which can be described exactly. It does not mean any polymers or, in general, no compounds with a molecular weight distribution. Smaller proportions of

Contamination, such as always occurs when using organic materials, should not invalidate the term "defined connection".

Organic electronic devices are preferred, characterized in that they contain a compound A of the formulas (1) to (4) (Scheme 1),

Forme! (1) Formula (2) Formula (3) Formula (4)

(Scheme 1) where the symbols used have the following meaning: Y is the same or different in each occurrence P, As, Sb or Bi in formula (1) and (3) and S, Se or Te in formula (2) and (4 ); X is the same or different at each occurrence NR ⁴ , O, S, Se or Te; R ¹ , R ² , R ³ is the same or different at each occurrence N (R ⁴ ) ₂ , a straight-chain, branched or cyclic alkyl group with 1 to 40 C atoms, which can be substituted with R ⁵ or unsubstituted, where a or more non-adjacent CH ₂ groups by -R ⁶ C = CR ⁶ -, -C ≡C-, Si (R ⁶ ) ₂ , Ge (R ⁶ ) ₂ , Sn (R ⁶ ) ₂ , C = O, C = S, C = Se, C = NR ⁶ , -O-, -S-, -NR ⁶ - or -CONR ⁶ - can be replaced and where one or more H atoms by F, Cl, Br, I, CN or NO ₂ can be replaced; several radicals R ¹ , R ² and / or R ³ can form a mono- or polycyclic, aliphatic or aromatic ring system with one another; or an aromatic or heteroaromatic system with 1 to 40 aromatic C atoms, which can be substituted by one or more radicals R ⁵ , where several substituents R ¹ , R ² and / or R ³ together are mono- or polycyclic, aliphatic or aromatic Can form a ring system, or an aromatic or heteroaromatic system with 1 to 40 aromatic carbon atoms bonded via a divalent group -Z-, where one or more hydrogen atoms can be replaced by F, Cl, Br or I or by one or more R ⁴ radicals can be substituted; several substituents R ¹ , R ² and / or R ^{3 can} span a further mono- or polycyclic, aliphatic or aromatic ring system; R ⁴ is the same or different at each occurrence a straight-chain, branched or cyclic alkyl or alkoxy chain with 1 to 22 C atoms, in which one or more non-adjacent C atoms by -R ⁶ C = CR ⁶ -, -C ≡C-, Si (R ⁶ ) ₂ , Ge (R ⁶ ) ₂ , Sn (R ⁶ ) ₂ , -NR ⁶ -, -O-, -S-, -CO-, -CO-O-, -O -CO-O- can be replaced, where one or more H atoms can also be replaced by fluorine, an aryl, heteroaryl or aryloxy group having 1 to 40 C atoms, which are also substituted by one or more R ⁶ radicals can, or OH, NH ₂ , NH (R ⁵ ) or N (R ⁵ ) ₂ ;

R ⁵ is the same or different at each occurrence R ⁴ or CN, B (R ⁶ ) ₂ or Si (R ⁶ ) ₃ ; Each occurrence of R ⁶ is the same or different H or an aliphatic or aromatic hydrocarbon radical having 1 to 20 C atoms;

Z is the same or different with each occurrence a conjugated radical with 1 to 40 C atoms, which is preferably in conjugation with the other two substituents, with the number of atoms of Z preferably linking the group Y = X and the aromatic radical , a is an even number, it being possible for one or more C atoms to be substituted by a radical R ⁵ or halogen; with the proviso that the molar mass of compound A is greater than 150 g / mol and less

Is 10,000 g / mol; and with the proviso that the following compounds are excluded from the invention:

An aromatic or heteroaromatic system in the sense of this invention is to be understood as a system which does not necessarily only contain aromatic or heteroaromatic groups, but in which two or more aromatic or heteroaromatic groups are also represented by a short, non-aromatic unit (preferably <10% of atoms other than H), such as. B. an sp ³ hybridized C, N or O atom may be interrupted. Thus, systems such as ^9,9' spirobifluorene, 9,9-DiaryIfluoren, triarylamine, etc., are to be understood as aromatic systems for the purposes of this application, for example.

In the context of the present invention, the radicals methyl, ethyl, n-propyl, i- are particularly preferably under a Cr to C ₂₂ alkyl group in which individual H atoms or CH ₂ groups can be substituted by the above-mentioned groups. Propyl, n-butyl, i-butyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl,

2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl or octynyl , Under a Ci to C ₂₂ -alkoxy group is particularly preferably methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy or

2-methylbutoxy understood. A CC ₄ o aromatic or heteroaromatic ring system, which can in each case still be substituted with the abovementioned R ³ radicals, is understood in particular to mean groups which are derived from benzene, naphthalene, biphenylene, terphenylene, fluorene, spirobifluorene, dihydrophenanthrene, tetrahydropyrene, ice - or trans-indofluorene,

Furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, Benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyrid imidazole, pyrazinimidazole, Quinoxaline imidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1, 2-thiazole, 1, 3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, pyrazine, phenazine, azacarbazolidine, 1, 2,3-triazoI, 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, 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.

Electronic devices in the sense of this invention are preferably organic

Electroluminescent devices (organic light-emitting diodes, OLEDs), organic thin-film transistors (O-TFTs), organic field-effect transistors (O-FETs), organic solar cells (O-SCs), organic photoreceptors or organic lasers (O-lasers), in particular organic electroluminescent devices ,

An organic electronic device is particularly preferred, characterized in that Y stands for P or S.

An organic electronic device is furthermore particularly preferred, characterized in that X stands for O. ,

Furthermore, an organic electronic device is particularly preferred, characterized in that at least one of the radicals R ¹ , R ² and / or R ^{3 represents} an aromatic or heteroaromatic system; in particular at least two of the radicals R ¹ , R ² and / or R ^{3 represent} an aromatic or heteroaromatic system.

If one of the radicals R ¹ , R ² and / or R ^{3 represents} an alkyl group, it is preferred if it has no hydrogen atoms in the α-position to the group Y = X. This is due to the increased acidity of the protons in this position and therefore the increased

Justify reactivity. Preferred alkyl groups are, for example, tert-butyl, adamantyl, norbornyl, etc.

Organic electronic devices are very particularly preferred, characterized in that the compounds containing units according to the formulas

(1), (2), (3) and (4) consist only of the elements carbon, hydrogen, oxygen and phosphorus or sulfur. It can also be preferred if the compound A contains more than one unit Y = X or more than one unit according to formulas (1) to (4). A group R ¹ or R ² or R ³ can then bridge two or more units Y = X.

Particularly suitable compounds of the formulas (1) to (4) have been found

Connections proven that are not planar. In particular, corresponding substituents R ¹ , R ² and / or R ³ can also cause the overall structure to deviate from planarity. This is the case in particular if at least one of the substituents R ¹ , R ² , R ³ and / or R ^{4 contains} at least one sp ³ hybridized carbon, silicon, germanium and / or nitrogen atom, which is thereby approximately tetrahedral or has pyramidal bond geometry in the case of nitrogen.

In order to achieve a clear deviation from the planarity, it is preferred if at least one of the sp ³ -hybridized atoms is a secondary, tertiary or quaternary atom, particularly preferably a tertiary or quaternary atom, very particularly in the case of carbon, silicon or germanium preferably a quaternary atom.

A secondary, tertiary or quaternary atom is understood to mean an atom with two, three or four substituents other than hydrogen.

Compounds which are present in at least one of the radicals R ¹ to

R ^{4 is} a 9.9'-spirobifluorene derivative, preferably linked via the 2 and / or 2.7 and / or 2.2 ^' and / or 2.2 ^' , 7 and / or 2.2 ^' , 7 , 7 ^' position, a 9,9-disubstituted fluorene derivative, preferably linked via the 2- and / or 2,7-position, a 6,6- and / or 12,12-di- or tetrasubstituted indenofluorene derivative

Triptycene derivative, preferably linked via the 9- and / or 10-position, a dihydrophenanthrene derivative, preferably linked via the 2- and / or 2,7-position, or a hexaarylbenzene derivative, preferably linked via the p-position on or on the aromatics. Compounds which are present in at least one of the radicals R ¹ to

R ⁴ contain a 9,9'-spirobifluorene derivative.

In a further preferred embodiment, at least one of the substituents R ¹ , R ² and / or R ^{3 is} a biaryl compound which is non-planar by rotation about the aryl-aryl axis. This is particularly the case when the at least one of the aryl groups, preferably both, are substituted in the ortho position to the aryl-aryl linkage, for example an ortho-linked biphenyl or a 1,1'-binaphthyl. Also preferred are compounds that are dendritic in structure. Also preferred are 1,3,5-trisubstituted benzenes.

Examples of suitable structures are the following Examples 1 to 52:

Compound A is preferably used as an electron transport material. An electron transport material is a material that predominantly conducts electrons in the electronic device.

An organic electronic device is furthermore preferred, characterized in that the layer containing compound A consists of at least 50%, preferably at least 80% of this compound and very particularly preferably only of compound A as a clean layer. However, the use of a mixture of compound A and further compounds can also be preferred. The other compounds can be both organic and inorganic, for example doping with a base metal, such as. B. alkali and / or alkaline earth metals, or with an organometallic compound such as. B. Co (Cp) ₂ or Ni (Cp) ₂ .

An organic electronic device is further preferred, characterized in that the compound A is amorphous and the glass transition temperature T _{g of} the compound A is greater than 100 ° C, particularly preferably greater than 130 ° C, in particular greater than 160 ° C. In addition to the layer containing the compound A, the organic electronic device can also contain further layers. These can be, for example: hole injection layer, hole transport layer, emission layer, hole blocking layer, electron transport layer and / or electron injection layer. At this point, however, it should be pointed out that each of these layers does not necessarily have to be present. An emission layer is necessarily present in an organic electroluminescent device.

A preferred aspect of the invention is an organic electroluminescent device according to the invention, comprising between the fluorescent device

Emission layer and the cathode at least one electron transport layer, characterized in that the electron transport material contains at least one compound A.

The thickness of the electron transport layer is preferably between 5 and 500 nm, particularly preferably between 10 and 100 nm, very particularly preferably between 20 and 70 nm.

It was found that the electron transport material according to the invention has a higher charge mobility compared to known electron transport materials, such as. B. AIQ ₃ , which has a technological

This is an advantage, as this allows the use of thicker layers of this material.

Another preferred aspect of the invention is an organic electroluminescent device according to the invention, characterized in that the

Emission layer contains at least one fluorescent emitter and at least one electron transport material, wherein the electron transport material contains at least one compound A. It is not absolutely necessary for the connection A to be present as a host in the layer to a large extent. Even a small proportion of compound A can be electron-conducting

Improve the properties of the emission layer significantly.

It may also be preferred if both an electron transport layer containing at least one compound A and an emission layer containing at least one compound A, which may be the same or different, are present in the organic electroluminescent device.

Furthermore, it can be preferred if, in an organic electroluminescent device, the emission layer which contains the compound A directly adjacent to the electron injection layer or to the cathode without using a separate electron transport layer. It can also be preferred if, in an organic electroluminescent device, the emission layer which contains the compound A is directly adjacent to the hole injection layer.

An organic electroluminescent device is further preferred, characterized in that the emitter (s) fluoresce with suitable excitation in the visible spectral range with one or more maxima between 380 nm and 750 nm. It may also be preferred if the emitters have several different emission maxima, so that white emission results overall.

Also preferred is an organic electronic device, characterized in that one or more layers are coated with a sublimation process. The materials are evaporated in vacuum sublimation systems at a pressure of less than 10 ^"5 mbar, preferably less than 10 ^{" 6} mbar, particularly preferably less than 10 ^"7 mbar.

An organic electronic device is also preferred, characterized in that one or more layers are coated with the OVPD (Organic Vapor Phase Deposition) process or with the aid of a carrier gas sublimation. The materials are at a pressure between 10 ^"5 mbar and

1 bar applied.

Also preferred is an organic electronic device, characterized in that one or more layers of solution, such as. B. by spin coating, or with any printing method, such as. B. screen printing, flexographic printing or offset printing, but particularly preferably LITI (Light Induced Thermal Imaging, thermal transfer printing) or ink-jet printing (ink jet printing).

The emitting devices described above now have the following surprising advantages over the prior art:

1. The efficiency of corresponding devices is higher compared to systems which contain AIQ ₃ as electron transport material according to the prior art. 2. The stability of corresponding devices becomes higher in comparison to systems which contain AIQ ₃ as electron transport material according to the prior art.

3. The operating voltage is significantly reduced. This increases performance efficiency. This is especially true when no separate electron transport layer is used.

4. In particular, blue OLEDs can be represented in better color purity, since the compounds A are colorless and do not impair the efficiency and the color of the OLED by re-absorption and re-emission. 5. Since the compounds A are generally not hygroscopic, they can be processed more easily and with less technical effort compared to AIQ ₃ . 6. Since the compounds A have a higher charge carrier mobility than electron transport materials according to the prior art, such as. B. AIQ ₃ , thicker electron transport layers can be used. As already described above, this is important for avoiding short circuits and is furthermore particularly necessary for the combination of fluorescent and phosphorescent OLEDs in a display, since the thicker layer thicknesses of the phosphorescent OLEDs must be compensated for by a thicker electron transport layer of the fluorescent OLEDs.

In the present application text and also in the following examples, the main target is organic light-emitting diodes and the corresponding displays. Despite this limitation of the description, it is possible for the person skilled in the art without further inventive step to use compounds A or compounds of the formulas (1) to (4) also for related devices, for. B. for organic solar cells, organic thin film transistors, organic field-effect transistors or organic laser diodes to use.

Examples:

Unless otherwise stated, the following syntheses were carried out under a protective gas atmosphere. The starting materials were from ALDRICH or ABCR (solvent, magnesium, n-BuLi, phosphorus trichloride, thionyl chloride). 2,2'-bis (diphenylphosphinoyI) -1, 1'-binaphthyl (H. Takaya et al., Organic Synthesis

1989, 67, 20) were prepared according to literature methods and cleaned as described below. Bis (9,9'-spirobifluoren-2-yl) phenylphosphine oxide (E1) and bis (9,9 ^' - spirobifluoren-2-yl) su! foxid (E3) were synthesized as described in WO 05/003253.

Synthesis example 1: rac-2,2'-bis (diphenylphosphinoyl) -1,1'-binaphthyl (E2) The 2,2'-bis (diphenylphosphinoyl) obtained according to the above-mentioned procedure

1, 1'-binaphthyl was purified as follows: First, 50 g of the crude product were placed in a Soxhlett extractor and extracted with chloroform through a glass fiber extraction thimble (pore size 0.1 μm). The chloroform was concentrated to a volume of 100 ml and 500 ml of ethanol were added. The resulting precipitate was filtered off and washed with ethanol.

The mixture was then stirred five times with 1000 ml of ethyl acetate under reflux. The sublimation was carried out at T = 325 ° C, p = 5 x 10 ^"5 mbar in a static vacuum. Tm = 308 ° C, T _g = 138 ° C. The yield of pure 2,2'-bis (diphenylphosphinoyl) - 1 , 1 -binapht yl was 37.3 g, with a purity of> 99.9% (according to HPLC).

Synthesis Example 2: tris (9,9 ^{'spirobifluorene-2-yl)} phosphine oxide (E4)

From 10.14 g (580 mmol) ausgeheiztem magnesium and a solution of 197.65 g (500 mmol) of 2-bromo-9,9 ^{'spirobifluorene} in a mixture of 1500 ml of THF, 300 ml dimethoxyethane and 4.8 ml (50 mmol) 1, 2 -Dichloromethane was a solution of the corresponding Grignard reagent. A mixture of 12.2 ml (140 mmol) of phosphorus trichloride in 200 ml of THF was added to this Grignard reagent at 20 ° C. for 30 min. dropwise. The mixture was then stirred under reflux for 3 h and at room temperature for 16 h. After 5 ml of water had been added, the reaction mixture was rotated in completely (1 mbar, 90 ° C.). The residue was taken up in 1000 ml of dichloromethane and washed three times with 500 ml of water.

A mixture of 21 ml of hydrogen peroxide (35% by weight) and 80 ml of water was added dropwise to the dichloromethane phase with very good stirring. After stirring for 24 h, the aqueous phase was separated. The organic phase was washed three times with 500 ml of water each time and then concentrated to a volume of 200 ml. After adding 1000 ml of ethanol, the fine crystalline

Aspirated precipitate and washed with 200 ml of ethanol. The purification was carried out by repeated recrystallization from DMSO (approx. 10 ml / g). Finally, it was dissolved in 1000 ml of NMP and precipitated at 100 ° C. by adding 1000 ml of ethanol in order to remove DMSO trapped in the crystal lattice. The sublimation took place at T = 445 ° c _ι p = 5 x 10 ^"5 mbar in a static vacuum. T _m = 433 ° C, T _g = 137 ° C. The yield of tris (9,9'-spirobifluoren-2-yl) phosphine oxide was 76.0 g (76 mmol), corresponding to 54.6% of theory, with a purity of> 99.9% (according to HPLC). ¹ H-NMR (CDCI ₃ ): D [ppm] = 7.80 (d, 3H), 7.73 ( dd, 6H), 7.64 (dd, 3H), 7.35 (dd, 3H), 7.28 (dd, 6H), 7.13 (dd, 3H), 7.09 (dd, 6H), 7.02 (dd, 6H), 6.69 (d , 3H), 6.55 (d, 6H).

³¹ P { ¹ H} -NMR (CDCI3): □ [ppm] = 31.6 (s).

Manufacture of OLEDs:

OLEDs were produced using a general process according to WO 05/003253, which in individual cases depends on the particular circumstances (e.g.

Layer thickness variation in order to achieve optimal efficiency or color) had to be adjusted.

The results of various OLEDs are presented in the following examples. The basic structure and layer thicknesses, besides that

Emission layer and the electron transport layer were identical for better comparability. Analogous to the above. general procedures, OLEDs with the following structure were generated:

Hole injection layer (HIL) 60 nm PEDOT (spun on water; obtained from H.C. Starck; poly (3,4-ethylenedioxy-2,5-thiophene)

Hole transport layer (HTM) 20 nm NaphDATA (evaporated; obtained from SynTec; 4,4 ', 4 "-Tris (N-1-naphthyl-N-phenylamino) - triphenylamine Hole transport layer (HTM) 20 nm S-TAD (evaporated; produced according to WO 99/12888; 2,2 ', 7,7'-tetrakis (diphenylamino) -spiro- 9,9'-bifluorene) emission layer (EML) 30 nm - 40 nm (for exact structure see examples in Table 1) electron conductor (ETL) 10 nm - 50 nm (for exact structure see examples in Table 1) (evaporated: AIQ ₃ obtained from SynTec; Tris (quinolinato) aluminum (III) or bis (9,9'-spirobifluoren-2-yl) phenyl -phosphine oxide) (synthesized according to the unpublished application DE 10330761.3)) Ba-Al (cathode) 3 nm Ba, then 150 nm Al. These OLEDs, which have not yet been optimized, have been characterized as standard; For this purpose, the electroluminescence spectra, the efficiency (measured in cd / A), the power efficiency (measured in Im / W) depending on the brightness, calculated from current-voltage-brightness characteristics (IUL characteristics), and the service life were determined. The time after which the initial brightness of the

OLED has dropped to half at a constant current density of 10 mA / cm ² . The layer thickness was optimized separately for each material for the electron transport layer. For a better comparison, however, the thicker AIQ ₃ layer thicknesses are also listed, which are directly comparable with the layer thicknesses from E1 to E4.

The results of some examples are summarized in Table 1, the composition of the ETL including the layer thicknesses being listed in each case. The ETLs contain, for example, the compound E1 bis (9,9'-spirobifluoren-2-yl) phenylphosphine oxide or the others as the electron transport material

Electron transport materials E2 to E4. Alternatively or additionally, these materials are also used in the emission layer. OLEDs which contain AIQ ₃ as the electron conductor according to the prior art serve as comparative examples. For better clarity, the corresponding structural formulas of the electron transport compounds used are shown below:

AIQ, E1

E2 E3

E4

The structures of the emitters used (or other components of the emission layer) are also shown below:

EM7

Table 1 :

All OLEDs show blue emission from the fluorescence emitters EM1 to EM7. This gives higher photometric efficiencies in devices in which the AIQ ₃ electron conductor has been replaced by the electron conductor according to the invention. Since the voltages required to achieve a certain brightness are also low here, very good power efficiency is obtained. The lifespan continues to increase.

In particular, with the same layer thickness of the ETL, the efficiencies, the power efficiencies, the service life and the color are better with the electron transport materials according to the invention than with the standard electron conductor AIQ ₃ .

In summary, it can be said that OLEDs, manufactured according to the new design principle, have a higher efficiency at lower voltages and a longer service life, as can easily be seen in Table 1.

Claims

claims:

1. Electronic device containing cathode, anode and at least one organic layer, characterized in that the organic layer contains at least one defined compound A with the chemical structural unit Y = X, the following being valid for the symbols used: Y is the same as each occurrence or different P, As, Sb, Bi, S, Se or Te; X is the same or different on each occurrence O, S, Se, Te or NR; R is the same or different each time an organic radical having 1 to 22 carbon atoms or OH or NH ₂ ; with the proviso that the compound A has a molecular weight of> 150 g / mol and <10000 g / mol and that the device contains no phosphorescent emitter; and with the proviso that the following compounds are excluded from the invention:

2. Electronic device according to claim 1, characterized in that it contains a compound A according to formula (1) to (4) (scheme 1),

Formula (1) Formula (2) Formula (3) Formula (4)

(Scheme 1) where the symbols used. have the following meanings: Y is the same or different in each occurrence P, As, Sb or Bi in formula (1) and (3) and S, Se or Te in formula (2) and (4); X is the same or different at each occurrence NR ⁴ , O, S, Se or Te; R ¹ , R ² , R ³ is the same or different at each occurrence N (R ⁴ ) ₂ , a straight-chain, branched or cyclic alkyl group with 1 to 40 C atoms, which can be substituted with R ⁵ or unsubstituted, where a or more non-adjacent -CH ₂ groups by -R ⁶ C = CR ⁶ -, -C = € -, Si (R ⁶ ) ₂ , Ge (R ⁶ ) ₂ , Sn (R ⁶ ) ₂ , C = O, C = S, C = Se, C = NR ⁶ , -O-, -S-, -NR ⁶ - or -CONR ⁶ - can be replaced and one or more H atoms can be replaced by F, Cl, Br, I, CN or NO ₂ ; several radicals R ¹ , R ² and / or R ³ can form a mono- or polycyclic, aliphatic or aromatic ring system with one another; or an aromatic or heteroaromatic system with 1 to 40 aromatic carbon atoms, which can be substituted by one or more radicals R ⁵ , where several substituents R ¹ , R ² and / or R ³ together are mono- or polycyclic, aliphatic or aromatic Can form a ring system, or an aromatic or heteroaromatic system with 1 to 40 aromatic C atoms bonded via a divalent group -Z-, where one or more H atoms can be replaced by F, Cl, Br or I or by one or more radicals R ⁵ can be substituted; several substituents R ¹ , R ² and / or R ^{3 can} span a further mono- or polycyclic, aliphatic or aromatic ring system; R ⁴ is the same or different at each occurrence a straight-chain, branched or cyclic alkyl or alkoxy chain with 1 to 22 C atoms, in which one or more non-adjacent C atoms by -R ⁶ C = CR ⁶ -, -C ≡C-, Si (R ⁶ ) ₂ , Ge (R ⁶ ) ₂ , Sn (R ⁶ ) ₂ , -NR ⁶ -, -O-, -S-, -CO-, -CO-O-, -O -CO-O- can be replaced, where one or more H atoms can be replaced by fluorine, an aryl, heteroaryl or an aryloxy group having 1 to 40 C atoms, which can also be substituted by one or more R ⁶ radicals , or OH, NH ₂ , NH (R ⁵ ) or N (R ⁵ ) ₂ ; R ⁵ is the same or different at each occurrence R ⁴ or CN, B (R ⁶ ) ₂ or Si (R ⁶ ) ₃ ; Each occurrence of R ⁶ is the same or different H or an aliphatic or aromatic hydrocarbon radical having 1 to 20 C atoms; Z is the same or different on each occurrence of a conjugated radical having 1 to 40 C atoms, where one or more C atoms can be substituted by a radical R ⁵ or halogen; with the proviso that the molar mass of compound A is greater than 150 g / mol and less than 10,000 g / mol; and with the proviso that the following compounds are excluded from the invention:

3. Electronic device according to claim 1 and / or 2, characterized in that Y stands for P or S.

4. Electronic device according to one or more of claims 1 to 3, characterized in that X stands for O.

Electronic device according to one or more of claims 2 to 4, characterized in that at least one of the radicals R ¹ , R ² and / or R ^{3 represents} an aromatic or heteroaromatic system.

6. Organic electronic device according to one or more of claims 1 to 5, characterized in that the compound A contains more than one unit Y = X or more than one unit according to formula (1) to (4).

7. Electronic device according to one or more of claims 1 to 6, characterized in that the compound of formula (1) to (4) are not planar.

8. Electronic device according to claim 7, characterized in that at least one of the substituents R ¹ , R ² , R ³ and / or R ^{4 contains} at least one sp ³ - hybridized carbon, silicon, germanium and / or nitrogen atom.

9. Electronic device according to claim 8, characterized in that wweenniiggsstteennss eeiinneess c of the sp ³ -hybridized atoms is a secondary, tertiary or quaternary atom

10. Electronic device according to claim 9, characterized in that at least one of the sp ³ -hybridized atoms is a quaternary atom.

11. Electronic device according to one or more of claims 1 to 10, characterized in that in at least one of the radicals R ¹ to R ^{4 is} a 9,9'-spirobifluorene derivative, a 9,9-disubstituted fluorene derivative, a 6,6- and /or 12,12-di- or tetrasubstituted indenofluorene derivative, a triptycene derivative, a dihydrophenanthrene derivative or a hexaarylbenzene derivative is contained.

12. Electronic device according to claim 11, characterized in that a 9,9'-spirobifluorene derivative is contained in at least one of the radicals R ¹ to R ⁴ .

13. Electronic device according to claim 7, characterized in that the non-planar radical R ¹ or R ² or R ^{3 represents} a biaryl group.

14. Electronic device according to one or more of claims 1 to 13, characterized in that the compound according to formulas (1) to (4) is selected from the example structures 1 to 52.

15. Electronic device according to one or more of claims 1 to 14, characterized in that the compound A is amorphous and the glass transition temperature T _{g of} the compound A is greater than 100 ° C.

16. Electronic device according to one or more of claims 1 to 15, characterized in that the compound A is used as an electron transport material.

17. Electronic device according to one or more of claims 1 to 16, characterized in that the layer containing compound A consists of at least 50% of this compound.

18. Electronic device according to claim 17, characterized in that the layer containing compound A consists only of this compound as a clean layer.

19. Electronic devices according to one or more of claims 1 to 18, characterized in that it is organic electroluminescent devices, organic thin film transistors, organic field-effect transistors, organic solar cells, organic photoreceptors or organic lasers.

20. Electronic device according to one or more of claims 1 to 19, characterized in that in addition to the layer containing the compound A, further layers are present.

21. Electronic device according to claim 20, characterized in that these further layers are selected from hole injection layer, hole transport layer, emission layer, hole blocking layer, electron transport layer and / or electron injection layer.

22. Electronic device according to one or more of claims 1 to 21, characterized in that at least one electron transport layer containing at least one compound A is contained between the fluorescent emission layer and the cathode.

23. Electronic device according to one or more of claims 1 to 22, characterized in that the emission layer contains at least one fluorescent emitter and at least one electron transport material, the electron transport material containing at least one compound A.

24. Electronic device according to one or more of claims 1 to 23, characterized in that both an electron transport layer containing at least one compound A, and an emission layer containing at least one compound A, which may be the same or different, are present.

25. Electronic device according to one or more of claims 1 to 24, characterized in that the emission layer which contains the compound A directly adjoins the electron injection layer or the cathode without using a separate electron transport layer.

26. Electronic device according to one or more of claims 1 to 25, characterized in that the emission layer containing the compound A directly adjoins the hole injection layer.

27. Electronic device according to one or more of claims 1 to 26, characterized in that it is an organic electroluminescent device in which the emitter (s) fluoresce with suitable excitation in the visible spectral range with one or more maxima between 380 nm and 750 nm ,