KR101708097B1 - Organic electro luminescence device - Google Patents

Abstract

The present invention relates to a positive electrode; cathode; And at least one organic compound layer interposed between the anode and the cathode, wherein the organic layer includes at least one selected from the group consisting of a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer, and an electron injecting layer, (Lifetime Enhancement Layer) between the first electrode and the second electrode.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic electroluminescence device,

The present invention relates to an organic electroluminescent device including at least one organic material layer.

In 1965, research on organic electroluminescent (EL) devices (hereinafter, simply referred to as 'organic EL devices') which resulted in blue electroluminescence using anthracene single crystals was carried on. In 1987, (NPB) and a light-emitting layer (Alq ₃ ). In order to realize high efficiency and long life characteristics required for commercialization, the organic EL device has an organic layer for injecting and transporting holes, an organic layer for electron injecting and transporting, and an organic layer for inducing electroluminescence A multilayer laminate structure in which characteristic and subdivided functions are imparted are proposed. The introduction of the multi-layer laminated structure improves the performance of the organic EL device to commercialization characteristics, and the application range from the car radio display product to the portable information display device and the TV display device is expanded in 1997.

The demand for a larger display and a higher resolution of a display has given the problem of high efficiency and long life of an organic EL device. In particular, in the case of high resolution realized by forming more pixels in the same area, the emission area of the organic EL pixel is reduced and the lifetime is reduced, and the most important technical problem that the organic EL device must overcome .

In the organic EL device, when current or voltage is applied to the two electrodes, holes are injected into the organic layer in the anode, and electrons are injected into the organic layer in the cathode. When the injected holes and electrons meet, an exciton is formed, and the exciton falls to a ground state and emits light. At this time, the organic EL element can be classified into a fluorescent EL element in which singlet excitons contribute to light emission and a phosphorescent EL element in which triplet excitons contribute to light emission, depending on the type of electron spin of the formed excitons.

Electron spins of excitons formed by recombination of electrons and holes are produced in the ratio of singlet excitons and triplet excitons of 25% and 75%. The fluorescent EL device which emits light by singlet excitons can not exceed 25% of the internal quantum efficiency theoretically according to the generation ratio, and the external quantum efficiency of 5% is accepted as the limit. Phosphorescent EL devices that emit light by triplet excitons can improve luminescence efficiency by up to 4 times compared to fluorescence when metal complex compounds containing transition metal heavy atoms such as Ir and Pt are used as phosphorescent dopants .

As described above, the phosphorescent EL device exhibits higher efficiency than that of fluorescence in terms of luminous efficiency on the basis of the theoretical facts. However, in the case of a blue phosphorescent device except for green and red, the phosphorescent dopant of the dark blue color and the phosphorescent dopant of high efficiency, As the development level of the gap is insufficient, blue phosphorescent devices have not been commercialized yet, and blue phosphorescent devices are used in products.

Research results have been reported for preventing the diffusion of holes into the electron transport layer to improve the stability of the device to improve the characteristics of the organic EL device described above. A technique has been disclosed in which the use of a material such as BCP or BPhen between the light emitting layer and the electron transporting layer prevents the holes from diffusing into the electron transporting layer and restricts the holes to the inside of the light emitting layer to effectively increase the recombination probability of holes and electrons. However, the derivatives such as BCP and BPhen used as the hole blocking layer have low oxidation stability to holes and poor heat resistance, and as a result, the lifetime of the organic EL device has been reduced and commercialization has not been achieved. In addition, since these materials merely function to block holes, the movement of electrons is inhibited and the driving voltage of the organic EL element is increased.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an organic EL device exhibiting high efficiency, low voltage, and particularly long life.

The present invention relates to a positive electrode; cathode; And at least one organic material layer selected from the group consisting of a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer and an electron injecting layer is provided between the anode and the cathode, and a lifetime improving layer is provided between the light emitting layer and the electron transporting layer Enhancement Layer (LEL).

Here, the lifetime improving layer may include a first bipolar compound having a different electron mobility and a second bipolar compound having both an electron attracting group (EWG) having a large electron absorbing property and an electron donating group (EDG) wherein the first bipolar compound and the second bipolar compound satisfy the following conditions (i) to (iv), respectively, and are mixed at a ratio of 1:99 to 99: 1 .

(i) the ionization potential [Ip (LEL)] is 5.5 eV or more,

(Ii) E _HOMO -E _LUMO > 2.9 eV,

(Iii) the triplet energy is greater than or equal to 2.3 eV,

(Iv) ΔEst <0.5 eV (ΔEst represents the difference between singlet energy and triplet energy of the compound)

The present invention can provide an organic electroluminescent device having a driving voltage, a luminous efficiency and a lifetime by introducing a life improving layer made of two or more different bipolar compounds into an organic electroluminescent device. Further, by applying the organic electroluminescent device of the present invention to a display panel, a display panel having improved performance and lifetime can be provided.

1 is a cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention.
2 is a graph showing the relative electron mobility of a bipolar compound contained in the life improving layer according to the present invention.
<Brief Description of Symbols>
100: anode 200: cathode
301: Hole injection layer 302: Hole transport layer
303: light emitting layer 304: life improving layer
305: electron transport layer 306: electron injection layer

Hereinafter, the present invention will be described.

The present invention relates to a positive electrode; cathode; And an organic material layer interposed between the anode and the cathode, wherein the organic material layer includes at least one selected from the group consisting of a hole injecting layer, a hole transporting layer, a light emitting layer, a life improving layer, an electron transporting layer and an electron injecting layer The Lifetime Enhancement Layer (LEL) has both an electron attracting group (EWG) having a large electron absorbing property and an electron donating group (EDG) having a large electron accepting property and having two or more electron mobility different from each other The present invention relates to an organic electroluminescent device including a bipolar compound, that is, a first bipolar compound and a second bipolar compound at the same time.

Here, the bipolar compound may be used as an electron transport layer, an electron injection layer, or both of them in addition to the life improving layer.

Hereinafter, description will be made with reference to FIG.

The anode 100 included in the organic electroluminescent device of the present invention injects holes into the organic material layer 300.

The material constituting the anode 100 is not particularly limited, and those known in the art can be used. Non-limiting examples thereof include metals such as vanadium, chromium, copper, zinc and gold; Alloys thereof; Metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); ZnO: Al, SnO _2: a combination of a metal and an oxide such as Sb; Conductive polymers such as polythiophene, poly (3-methylthiophene), poly [3,4- (ethylene-1,2-dioxy) thiophene] (PEDT), polypyrrole and polyaniline; And carbon black.

The method for producing the anode (100) is not particularly limited, and can be produced according to a conventional method known in the art. For example, a method of coating a positive electrode material on a substrate made of a silicon wafer, quartz, a glass plate, a metal plate, or a plastic film can be mentioned.

The cathode 200 included in the organic electroluminescent device of the present invention injects electrons into the organic material layer 300.

The material forming the cathode 200 is not particularly limited, and any material known in the art can be used. Non-limiting examples thereof include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin and lead; Alloys thereof; And multilayer structured materials such as LiF / Al and LiO ₂ / Al.

Also, the method for producing the cathode 200 is not particularly limited, and may be manufactured by a method known in the art.

For example, the hole injection layer 301, the hole transport layer 302, the light emitting layer 303, and the light emitting layer 303 may be used as the organic material layer 300 of the organic EL device according to the present invention. ), A lifetime improving layer 304, an electron transporting layer 305, and an electron injection layer 306. The electron transport layer 305 may be formed of a metal such as aluminum, In this case, in consideration of the characteristics of the organic electroluminescent device, it is preferable to include all of the organic layers described above.

The hole injection layer 301 and the hole transport layer 302 included in the organic material layer 300 of the present invention serve to move the holes injected from the anode 100 to the light emitting layer 303. The material for forming the hole injection layer 301 and the hole transport layer 302 is not particularly limited as long as the material has a low hole injection barrier and a high hole mobility and the hole injection layer / have. Non-limiting examples thereof include arylamine derivatives.

The light emitting layer 303 included in the organic material layer 300 of the present invention is a layer in which excitons are formed by the combination of holes and electrons and the color of the light emitted by the organic light emitting device varies depending on the material forming the light emitting layer 303 . The light emitting layer 303 may include a host and a dopant. The host preferably includes 70 to 99.9% by weight of the host and 0.1 to 30% by weight of the dopant.

More specifically, when the light emitting layer 303 is blue fluorescence, green fluorescence or red fluorescence, the host may be contained in an amount of 80 to 99.9% by weight and the dopant may be contained in an amount of 0.1 to 20% by weight. When the light emitting layer 303 is a blue fluorescent light, a green fluorescent light, or a red phosphorescent light, the host may include 70 to 99 wt% and the dopant may include 1 to 30 wt%.

The host included in the light emitting layer 303 is not particularly limited as long as it is well known in the art, and examples thereof include alkali metal complex compounds; Alkaline earth metal complex compounds; Or condensed aromatic ring derivatives.

More specifically, the host material may be at least one selected from the group consisting of aluminum complexes, beryllium complexes, anthracene derivatives, pyrene derivatives, triphenylene derivatives, carbazole derivatives, dibenzofuran derivatives, Benzothiophene derivatives, or a combination of at least one thereof.

The dopant included in the light emitting layer 303 is not particularly limited as long as it is well known in the art, and examples thereof include an anthracene derivative, a pyrene derivative, an arylamine derivative, iridium (Ir), or platinum (Pt) And the like.

The above-described light emitting layer 303 may be a single layer, or a plurality of layers of two or more layers. Here, when the light emitting layer 303 is a plurality of layers, the organic electroluminescent device can emit light of various colors. Specifically, the present invention is characterized in that a light emitting layer composed of a plurality of single materials is provided between the hole transporting layer 302 and the life improving layer 304, or a plurality of light emitting layers made of different materials are provided in series, A light emitting element can be provided. In addition, when a plurality of light emitting layers is included, the driving voltage of the device is increased, while the current value in the organic light emitting device is constant, thereby providing an organic electroluminescent device having improved luminous efficiency by the number of light emitting layers.

The life improving layer 304 included in the organic material layer 300 of the present invention is provided between the light emitting layer 303 and the electron transporting layer 305 to improve the lifetime of the organic electroluminescence device.

The material forming the life-improving layer 304 is not particularly limited. However, the material having both the electron attracting group (EWG) having a large electron absorbing property and the electron donating group (EDG) It is preferable to use a bipolar compound of at least two species, that is, a mixture of the first bipolar compound and the second bipolar compound.

More specifically, the two or more kinds of bipolar compounds having different electron mobilities may have an ionization potential of 5.5 eV or more, specifically 5.5 to 7.0 eV, preferably 5.5 to 6.5 eV, .

The difference (E _HOMO -E _LUMO ) between the HOMO value and the LUMO value of the two or more kinds of bipolar compounds having different electron mobilities is more than 2.9 eV and more specifically 2.9 eV to 3.5 eV .

The triplet energies may each be in the range of 2.3 eV or more, specifically 2.3 to 3.5 eV, and preferably 2.3 to 3.0 eV. In addition, the singlet energy and the triplet energy difference (ΔEst) of the bipolar compound are each less than 0.5 eV, specifically less than 0.5 eV and more than 0.01 eV.

Since the bipolar compound has an ionization potential of 5.5 eV or more, it can prevent the hole from diffusing or moving into the electron transport layer 305 when used in the lifetime improving layer 304, thereby improving the lifetime of the organic electroluminescent device.

That is, holes move on the ionization potential level in the organic electroluminescent device. When holes are diffused or moved to the electron transport layer 305 through the light emitting layer 303, irreversible decomposition reaction by oxidation occurs, The lifetime of the device is lowered.

In contrast, in the present invention, since the lifetime improving layer 304 made of two or more kinds of bipolar compounds having an ionization potential [Ip (LEL)] of 5.5 eV or more is provided, the holes are prevented from diffusing or moving to the electron transporting layer 305 Therefore, the lifetime of the organic electroluminescent device can be improved. That is, the holes are blocked by the high energy barrier of the lifetime enhancement layer 304 and do not diffuse or move to the electron transport layer 305, and remain in the emission layer 303.

When the light emitting layer 303 is made of a red phosphor, the ionization potentials of the two or more kinds of bipolar compounds contained in the life improving layer 304 may be 5.5 eV or more, respectively, but they may be green phosphors or blue phosphors The ionization potential of the bipolar compound is preferably 6.0 eV or more.

On the other hand, in the bipolar compound, since the difference ( _HOMO- E _LUMO ) between the HOMO value and the LUMO value exceeds 2.9 eV, the triplet energy is 2.3 eV or more, and the singlet energy and triplet energy difference are less than 0.5 eV, When this is used for the life improving layer 304, the excitons formed in the light emitting layer 303 are prevented from diffusing into the electron transporting layer 305, and the phenomenon of light emission at the interface between the light emitting layer 303 and the electron transporting layer 305 is also prevented . As a result, the spectrum of the organic electroluminescent device is prevented from being mixed and the stability of the organic electroluminescent device is improved, thereby improving the lifetime of the organic electroluminescent device.

More specifically, two or more kinds of bipolar compounds having different electron mobilities have both electron attracting electrons (EWG) and electron donating electrons (EDG), and the electron clouds of HOMO and LUMO are separated . (DELTA Est) between the triplet energy and the singlet energy of the compound is small and the relation of DELTA Est < 0.5 eV is satisfied. Therefore, even if the difference ( _HOMO- E _LUMO ) between the HOMO value and the LUMO value exceeds 2.9 eV, And may have an anti-energy (T1).

When the light emitting layer 303 is made of a red phosphorescent material, the triplet energy of the two or more kinds of bipolar compounds contained in the lifetime improving layer 304 may be 2.3 eV or more. When the light emitting layer is made of a green phosphorescent material, eV and blue phosphorescent material, respectively, it is preferably 2.7 eV or more.

If electrons and holes are not balanced due to the difference between the number of holes injected from the anode 100 and the number of electrons injected from the cathode 200, electrons or holes that can not form excitons due to recombination are injected into the light emitting layer 303 ). The electrons or holes accumulated in the light emitting layer 303 may not be smoothly oxidized and reduced in the light emitting layer 303 or may affect the adjacent layers to reduce the lifetime of the organic light emitting device.

On the contrary, when the bipolar compounds having different electron mobilities have hole mobility and electron mobility of 1 × 10 ^-6 cm ² / V · s or more at room temperature, when they are used for the life improving layer 304 The injection of electrons is prevented from being delayed as compared with the number of holes injected from the anode 100, and the lifetime of the organic electroluminescent device can be improved.

Indeed, in the two or more kinds of bipolar compounds contained in the life improving layer 304 of the present invention, the mobility of holes is 1 × 10 ^-6 cm ² / V · s or more at room temperature due to the electron donor (EDG) When the electron mobility is more than 1 × 10 ^-6 cm ² / V · s at the room temperature due to the EWG and is used for the lifetime improving layer 304, electrons can be effectively injected into the light emitting layer 303. When the electron injection into the light emitting layer 303 is smooth, the efficiency of forming the exciton in the light emitting layer 303 increases, and the lifetime of the organic light emitting device can be improved.

The life improving layer 304 according to the present invention includes two or more bipolar compounds having different electron mobilities, preferably a first bipolar compound and a second bipolar compound.

More specifically, the present invention comprises a first bipolar compound and a second bipolar compound having different electron mobilities, wherein the electron mobility is relatively higher than that of the first bipolar compound The life improving layer 304 of the present invention further including a fast second bipolar compound improves the efficiency while maintaining the life of the life improving layer 304 including the first bipolar compound singly. The second amphiphilic compound, which has a relatively high electron mobility, improves the efficiency while contributing to the formation of excitons by facilitating the movement of electrons.

On the other hand, the life improving layer 304 of the present invention, which further includes a second bipolar compound having a relatively low electron mobility as compared to the first bipolar compound, has a lifetime improvement including a single bipolar compound Lt; RTI ID = 0.0 &gt; 304 &lt; / RTI &gt; The second bipolar compound having a relatively low electron mobility improves the lifetime by reducing the degradation phenomenon of electrons or holes adjacent to the exciton.

Two or more kinds of bipolar compounds which are included in the material of the life improving layer 304 of the present invention and whose electron mobilities are different from each other may be selected from the group consisting of a moiety having electron attracting (EWG) And a moiety having this large electron donor (EDG) characteristic is formed by bonding. (EWG) moiety represented by the following formula as an electron withdrawing group (EWG).

In this formula,

A ₁ to A ₁₁ are the same or different and are each independently N or C (R) and at least one is N, wherein plural R's are the same or different, To form a fused condensed ring. For example, a plurality of A ₁ to A ₆ , which are not N but C (R), such as A ₁ and A ₂ , A ₂ and A ₃ , A ₃ and A ₄ , A ₄ and A ₅ , A ₅ and A ₆ , Or A ₆ and A ₁ may combine with each other to form a condensed ring, and a plurality of A ₇ to A ₁₁ , such as A ₇ and A ₈ , A ₈ and A ₉ , A ₉ and A ₁₀ , A ₁₀ and A ₁₁ , and A ₁₁ and A ₇ may combine with each other to form a condensed ring.

A plurality of R's are the same or different and are each independently selected from the group consisting of hydrogen, deuterium, a halogen group, a cyano group, a nitro group, an amino group, a C ₁ to C ₄₀ alkyl group, a C ₂ to C ₄₀ alkenyl group , A C ₂ to C ₄₀ alkynyl group, a C ₃ to C ₄₀ cycloalkyl group, a heterocycloalkyl group having 3 to 40 nuclear atoms, a C ₆ to C ₆₀ aryl group, a heteroaryl group having 5 to 60 nuclear atoms, A C ₁ to C ₄₀ alkyloxy group, a C ₆ to C ₆₀ aryloxy group, a C ₁ to C ₄₀ alkylsilyl group, a C ₆ to C ₆₀ arylsilyl group, a C ₁ to C ₄₀ alkylboron group, arylboronic group of C ₆ ~ C _60, C ₁ ~ C ₄₀ is selected from the phosphine group, C ₁ ~ C ₄₀ phosphine oxide group, and the group consisting of C ₆ ~ C ₆₀ aryl group of an amine of,

The alkyl group, alkenyl group, alkynyl group, cycloalkyl group, heterocycloalkyl group, aryl group, heteroaryl group, alkyloxy group, aryloxy group, alkylsilyl group, arylsilyl group, alkylboron group, arylboron group, pingi, phosphine oxide group and an arylamine group, each independently, a deuterium, a halogen group, a cyano group, a nitro group, an amino group, C ₁ ~ C ₄₀ alkyl group, C ₂ ~ C ₄₀ alkenyl group, C ₂ ~ C ₄₀ of the An alkynyl group, a C ₃ to C ₄₀ cycloalkyl group, a heterocycloalkyl group having 3 to 40 nuclear atoms, a C ₆ to C ₄₀ aryl group, a heteroaryl group having 5 to 40 nuclear atoms, a C ₁ to C ₄₀ alkyl A C ₆ to C ₆₀ aryloxy group, a C ₁ to C ₄₀ alkylsilyl group, a C ₆ to C ₆₀ arylsilyl group, a C ₁ to C ₄₀ alkylboron group, a C ₆ to C ₆₀ aryl boron group, C ₁ ~ C ₄₀ is the force may be substituted with pingi, C ₁ ~ C ₄₀ of the phosphine oxide group, and a C ₆ ~ 1 or more selected from the group consisting of C ₆₀ arylamines.

The electron withdrawing moiety (EWG) moiety is a nitrogenous heteroaromatic hydrocarbon having 5 or 6 nucleus atoms in which one to three carbons are substituted with nitrogen. In addition, the moiety may include a form in which two or more rings are pendant or condensed with each other, or a condensed form with an aryl group.

In the present invention, the electron withdrawing group (EWG) moiety may be more specifically a structure represented by the following formula, and is preferably a 6-membered nitrogen heteroaromatic hydrocarbon containing 1 to 3 nitrogen atoms. Non-limiting examples of preferred electron withdrawing moieties (EWG) include pyridine, pyrimidine, triazine, pyrazine, and the like.

The carbon or nitrogen atom of the moiety having an electron withdrawing (EWG) characteristic with a high electron absorbing property forms a bond with a moiety having electron donor (EDG) characteristics.

The two or more bipolar compounds which are included as materials for the life improving layer 304 of the present invention and have different electron mobility include an electron donor (EDG) moiety represented by the following formula (1).

Non-limiting examples of such moieties having large electron donor (EDG) properties include electron-dense nitrogen heteroaromatic rings such as indole, carbazole, and azepine; Or condensed polycyclic aromatic rings such as biphenyl, triphenylene, and fluorocene may be used. More specifically, the condensed polycyclic aromatic rings may be represented by the following formula (1).

In Formula 1,

X ₁ is selected from the group consisting of O, S, Se, N ( Ar 1), C (Ar 2) (Ar 3) and _{Si (Ar 4) (Ar 5} ),

Y ₁ to Y ₄ are the same or different and are each independently N or C (R ₁ ), wherein a plurality of R _{1 s} may be the same or different from each other, and they may form a condensed ring with an adjacent group Have;

X ₂ and X ₃ are the same or different and are each independently N or C (R ₂ ), wherein a plurality of R _{2 s} may be the same or different, and they may form a condensed ring with adjacent groups Have;

Wherein R ₁ to R _2, and Ar ₁ to Ar ₅ are the same or different and are each independently hydrogen, deuterium, halogen group, cyano group, nitro group, amino _{group, C 1 ~ C 40, C} 2 ~ C ₄₀ to C ₄₀ alkenyl, C ₂ to C ₄₀ alkynyl, C ₃ to C ₄₀ cycloalkyl, heterocyclic cycloalkyl having 3 to 40 nuclear atoms, C ₆ to C ₆₀ aryl, C ₁ -C ₄₀ alkyloxy, C ₆ -C ₆₀ aryloxy, C ₁ -C ₄₀ alkylsilyl, C ₆ -C ₆₀ arylsilyl, C ₁ -C ₄₀ alkyl, An aryl boron group of C ₆ to C ₆₀ , a phosphine group of C ₁ to C ₄₀ , a phosphine oxide group of C ₁ to C ₄₀ , and an arylamine group of C ₆ to C ₆₀ ,

The alkyl group, alkenyl group, alkynyl group, cycloalkyl group, heterocycloalkyl group, aryl group, heteroaryl group, alkyloxy group, aryloxy group, alkylsilyl group and arylsilyl group of R ₁ to R ₂ and Ar ₁ to Ar ₅ A halogen atom, a cyano group, a nitro group, an amino group, a C ₁ to C ₄₀ alkyl group, a C ₂ to C ₄₀ alkyl group, an aryloxy group, an aryloxy group, A C ₂ to C ₄₀ alkynyl group, a C ₃ to C ₄₀ cycloalkyl group, a heterocycloalkyl group having 3 to 40 nuclear atoms, a C ₆ to C ₄₀ aryl group, a heteroatom having 5 to 40 nuclear atoms An aryl group, a C ₁ to C ₄₀ alkyloxy group, a C ₆ to C ₆₀ aryloxy group, a C ₁ to C ₄₀ alkylsilyl group, a C ₆ to C ₆₀ arylsilyl group, a C ₁ to C ₄₀ alkyl At least one member selected from the group consisting of a boron group, an arylboron group of C ₆ to C ₆₀ , a phosphine group of C ₁ to C ₄₀ , a phosphine oxide group of C ₁ to C ₄₀ , and an arylamine group of C ₆ to C ₆₀ &Lt; / RTI &gt;

In the present invention, the above-mentioned formula (1) may be further specified by any one of the following A-1 to A-24. However, the present invention is not limited thereto.

In the above A-1 to A-24,

R ₂ , Y ₁ to Y _4, and Ar ₁ to Ar ₅ are the same as in the above-described formula (1). In view of the physical and chemical properties of the compound, it is preferable that A-1 to A-6 are used.

In the present invention, the formula (1), which is an electron donor (EDG) moiety, may be used alone in the structure of the formula (1), or may be condensed in combination with the formula (2) or (3).

More specifically, Y ₁ to Y ₄ in formula ( ₁ ) are each independently N or C (R ₁ ), and when they are plural C (R ₁ ), Y ₁ and Y ₂ , Y ₂ and Y ₃ or Y ₃ And Y &lt; ₄ &gt; form a condensed ring with the following formula (2). The plurality of R &lt; ₁ &gt; s may be the same or different from each other.

When X ₂ and X ₃ are both C (R ₂ ) in the general formula (1), the plurality of R ₂ may bond with the following general formula (2) or (3) to form a condensed ring.

In the general formulas (2) and (3)

Y ₅ to Y ₁₄ are the same or different and each independently N or C (R ₃ ), wherein when there are a plurality of C (R ₃ ) s, the plurality of R _{3 s} are the same or different, To form a condensed ring,

X ₄ is the same as X ₁ , wherein a plurality of Ar ₁ to Ar ₅ are the same or different.

A plurality of R ₃ to form a condensed ring ratio (非), even if the same displays the same or different, each independently, a hydrogen, deuterium, halogen group, cyano group, nitro group, amino group, C ₁ ~ C ₄₀ An alkyl group, a C ₂ to C ₄₀ alkenyl group, a C ₂ to C ₄₀ alkynyl group, a C ₃ to C ₄₀ cycloalkyl group, a heterocyclic cycloalkyl group having 3 to 40 nuclear atoms, a C ₆ to C ₆₀ aryl group, A heteroaryl group having 5 to 60 atoms, a C ₁ to C ₄₀ alkyloxy group, a C ₆ to C ₆₀ aryloxy group, a C ₁ to C ₄₀ alkylsilyl group, a C ₆ to C ₆₀ arylsilyl group, C ₁ ~ alkyl boron C ₄₀ group, C ₆ ~ C ₆₀ aryl boron group, C ₁ ~ C ₄₀ of the phosphine group, C ₁ ~ C ₄₀ phosphine oxide group, and a C ₆ ~ consisting of an aryl amine of the C ₆₀ of the &Lt; / RTI &gt;

Alkyl group of the R _3, an alkenyl group, an alkynyl group, a cycloalkyl group, a heterocycloalkyl group, an aryl group, a heteroaryl group, an alkyloxy group, an aryloxy group, an alkylsilyl group, an arylsilyl group, an alkyl boron group, an aryl boron group, phosphine group, a phosphine oxide group and an arylamine group, each independently, a deuterium, a halogen group, a cyano group, a nitro group, an alkenyl group of an amino group, C ₁ ~ C ₄₀ alkyl group, C ₂ ~ C ₄₀ of the group, C ₂ ~ C ₄₀ the alkynyl group, C ₃ ~ C ₄₀ cycloalkyl group, a nuclear atoms, 3 to 40 hetero cycloalkyl group, C ₆ ~ of the C ₄₀ of the aryl group, the number of nuclear atoms of 5 to 40 heteroaryl group, C ₁ ~ C ₄₀ An alkyloxyl group, a C ₆ to C ₆₀ aryloxy group, a C ₁ to C ₄₀ alkylsilyl group, a C ₆ to C ₆₀ arylsilyl group, a C ₁ to C ₄₀ alkylboron group, a C ₆ to C ₆₀ aryl boron group, C ₁ ~ C ₄₀ of the phosphine group, C ₁ ~ C ₄₀ of the phosphine oxide group, and a C ₆ ~ substituted by one or more selected from the group consisting of C ₆₀ aryl amine, or It may be substituted.

In the present invention, the compound formed by condensation of the above-mentioned formulas (1) and (2) may be further compounded by any one of the compounds represented by the following formulas (1a) to (1f).

 [Formula 1a]

[Chemical Formula 1b]

[Chemical Formula 1c]

&Lt; RTI ID = 0.0 &

[Formula 1e]

(1f)

In the above general formulas (1a) to (1f)

X ₁ to X ₄ and Y ₁ to Y ₈ are as defined in formulas (1) and (2).

According to a preferred embodiment of the present invention, Y ₁ to Y ₄ which form a condensed ring are N or C (R ₁ ) and are all C (R ₁ ), and Y ₅ to Y ₈ are N Or C (R ₃ ), and both are C (R ₃ ). Wherein a plurality of R ₁ and R ₃ are the same or different from each other.

The compounds of the present invention in which the above-mentioned formulas (1) and (2) are condensed can be embodied by any of the following formulas (B-1) to (B-30). However, the present invention is not limited thereto.

In the above Formulas B-1 to B-30,

Ar ₁ and R ₁ to R ₃ are the same as defined in formulas (1) and (2).

More specifically, Ar ₁ is a substituted or unsubstituted C ₆ -C ₄₀ aryl group, or a substituted or unsubstituted heteroaryl group having 5 to 40 nucleus atoms,

R ₁ to R ₃ are each independently hydrogen, a substituted or unsubstituted C ₁ to C ₄₀ alkyl group, a substituted or unsubstituted C ₆ to C ₄₀ aryl group, or a substituted or unsubstituted 5 to 40 Gt; is preferably a heteroaryl group of &lt; RTI ID = 0.0 &gt;

Herein, the formulas B-1 to B-30 having the condensed structures of the above-mentioned formulas (1) and (2) include at least one condensed indole or condensed carbazole moiety.

In the present invention, the compounds formed by condensation of formulas (1) and (3) may be embodied in any one of the compounds represented by the following formulas (1g) to (1n).

 [Formula 1g]

[Chemical Formula 1h]

[Formula 1i]

[Chemical Formula 1j]

[Chemical Formula 1k]

&Lt; EMI ID =

[Formula 1m]

[Formula 1n]

X ₁ , X ₃ to X _4, and Y ₁ to Y ₁₄ are as defined in formulas (1) and (3).

More preferably, X ₁ and X ₄ are the same or different, and each independently is O, S or N (Ar ₁ ), more preferably N (Ar ₁ ) ₁ are the same or different.

Y ₁ to Y ₄ are the same or different and are each independently N or C (R ₁ ), and it is preferable that Y ₁ to Y ₄ are both C (R ₁ ), wherein a plurality of R ₁ are the same Or different.

X ₃ is each independently N or C (R ₂ )

Y ₅ to Y ₁₄ are the same or different and are each independently N or C (R ₃ ), preferably Y ₅ to Y ₁₄ are both C (R ₃ ), wherein a plurality of R ₃ is the same Or different.

Here, Ar ₁ and R ₁ to R ₃ are the same as those defined in formulas (1) and (3).

According to a preferred embodiment of the present invention, X ₁ and X ₄ are each independently N (Ar ₁ ) or S in the general formulas (1a) to (1n). That is, it is preferable that X ₁ is N (Ar ₁ ), X ₄ is S, X ₁ is S, X ₄ is N (Ar ₁ ), or X ₁ and X ₄ are both N (Ar ₁ ).

In the compounds represented by Chemical Formulas (1a) to (1n), Ar ₁ is preferably a substituted or unsubstituted C ₆ -C ₆₀ aryl group, or a substituted or unsubstituted heteroaryl group having 5 to 60 nuclear atoms, Ar ₂ to Ar ₅ are the same or different and each independently represents a substituted or unsubstituted C ₁ to C ₄₀ alkyl group (specifically, a methyl group) or a substituted or unsubstituted C ₆ to C ₆₀ aryl group Is preferably a phenyl group).

Here, the above formula (1) and (3) having the condensed structure have one or more condensed azine-fused moieties, so that the electron donor has a characteristic of a strong electron donor (EDG).

In the present invention, the two or more bipolar compounds which are included in the material for improving lifetime and have different electron mobility include electron moles represented by the following formula (4) include moieties having a large electron donor (EDG) .

 [Chemical Formula 4]

In Formula 4,

L ₁ to L ₃ are the same or different and each independently selected from a single bond, a C ₆ to C ₆₀ arylene group, and a heteroarylene group having 5 to 60 nuclear atoms,

Ar ₆ to Ar ₈ are the same or different and are each independently selected from the group consisting of hydrogen, deuterium, a C ₆ to C ₄₀ aryl group, and a heteroaryl group having 5 to 40 nuclear atoms, with the proviso that Ar ₆ To Ar &lt; ₈ &gt; are all the same,

R ₄ to R ₆ are the same or different and are each independently selected from the group consisting of hydrogen, deuterium, halogen, cyano, nitro, amino, C ₁ to C ₄₀ alkyl, C ₂ to C ₄₀ alkenyl, C _A C ₃ to C ₄₀ cycloalkyl group, a heterocyclic cycloalkyl group having 3 to 40 nuclear atoms, a C ₆ to C ₆₀ aryl group, a heteroaryl group having 5 to 60 nuclear atoms, a C ₁ to C ₄₀ alkynyl group, ~ C ₄₀ alkyloxy group of, C ₆ ~ aryloxy C _60, C ₁ ~ C ₄₀ alkyl silyl group, C ₆ ~ aryl silyl group of C _60, C ₁ ~ C ₄₀ group of an alkyl boron, C ₆ An arylboron group of C ₆₀ , a phosphine group of C ₁ to C ₄₀ , a phosphine oxide group of C ₁ to C ₄₀ , and an arylamine group of C ₆ to C ₆₀ ,

a to c each independently represents an integer of 0 to 3,

Wherein L ₁ to L _3, R ₄ to R ₆ and Ar ₆ to Ar ₈ aryl group, a heteroaryl group, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a heterocycloalkyl group, an aryl group, a heteroaryl group, alkyloxy An aryl group, an aryloxy group, an aryloxy group, an alkylsilyl group, an arylsilyl group, an alkylboron group, an arylboron group, a phosphine group, a phosphine oxide group and an arylamine group are each independently selected from the group consisting of deuterium, a halogen group, a cyano group, C ₁ ~ C ₄₀ alkyl group, C ₂ ~ C ₄₀ alkenyl group, C ₂ ~ C ₄₀ of the alkynyl group, C ₃ ~ C ₄₀ cycloalkyl group, nuclear atoms, 3 to 40 heterocycloalkyl group of, C ₆ ~ C of _A C ₁ to C ₄₀ alkyloxy group, a C ₆ to C ₆₀ aryloxy group, a C ₁ to C ₄₀ alkylsilyl group, a C ₆ to C ₄₀ aryl group, a heteroaryl group having 5 to 40 nuclear atoms, a C ₁ to C ₄₀ alkyloxy group, ₆₀ arylsilyl group, a alkyl boronic of _{C 1 ~ C 40, C 6} ~ C group ₆₀ arylboronic of, C ₁ ~ C ₄₀ of the phosphine group, C ₁ ~ phosphine oxide of a C ₄₀ group, and a C ₆ ~ C ₆₀ Arylas And may be unsubstituted or substituted with at least one member selected from the group consisting of

More specifically, in the formula (4), L ₁ to L ₃ are the same or different and each independently selected from a single bond, a C ₆ to C ₆₀ arylene group, and a heteroarylene group having 5 to 60 nuclear atoms Preferably a single bond, a C ₆ to C ₁₈ arylene group, or a heteroarylene group having 5 to 18 nucleus atoms. For example, a single bond, phenylene, biphenylene, carbazolylene.

Ar ₆ to Ar ₈ are the same or different and are each independently selected from the group consisting of hydrogen, deuterium, a C ₆ to C ₄₀ aryl group, and a heteroaryl group having 5 to 40 nucleus atoms, wherein Ar ₆ To Ar ₈ is preferably selected from a heteroaryl group having 5 to 40 nuclear atoms and containing at least one element selected from the group consisting of N, O and S. Provided that Ar ₆ to Ar ₈ are not the same.

In the present invention, at least one of R ₁ to R ₆ and Ar ₁ to Ar ₈ in the compound represented by any one of Chemical Formulas (1) to (1) and Chemical Formula (4) is a moiety having electron attracting Lt; / RTI &gt;

In the present invention, alkyl is a monovalent substituent derived from a linear or branched saturated hydrocarbon having 1 to 40 carbon atoms, and examples thereof include methyl, ethyl, propyl, isobutyl, sec-butyl, pentyl, iso-amyl, .

The alkenyl in the present invention is a monovalent substituent derived from a linear or branched unsaturated hydrocarbon having 2 to 40 carbon atoms and having at least one carbon-carbon double bond. Examples thereof include vinyl, allyl, Isopropenyl, 2-butenyl, and the like.

Alkynyl in the present invention is a monovalent substituent derived from a linear or branched unsaturated hydrocarbon having 2 to 40 carbon atoms and having at least one carbon-carbon triple bond. Examples thereof include ethynyl, 2- 2-propynyl, and the like.

The aryl in the present invention means a monovalent substituent derived from an aromatic hydrocarbon having 6 to 60 carbon atoms in which a single ring or two or more rings are combined. Also, a form in which two or more rings are pendant or condensed with each other may be included. Examples of such aryl include phenyl, naphthyl, phenanthryl, anthryl and the like.

The heteroaryl in the present invention means a monovalent substituent derived from a monoheterocyclic or polyheterocyclic aromatic hydrocarbon having 5 to 40 nuclear atoms. Wherein at least one of the carbons, preferably one to three carbons, is replaced by a heteroatom such as N, O, S or Se. In addition, the ring may be pendant or condensed with each other, or may be condensed with an aryl group. Examples of such heteroaryls include 6-membered monocyclic rings such as pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, phenoxathienyl, indolizinyl, indolyl indolyl), purinyl, quinolyl, benzothiazole, carbazolyl, 2-furanyl, N-imidazolyl, 2- isoxazolyl , 2-pyridinyl, 2-pyrimidinyl, and the like.

In the present invention, aryloxy is a monovalent substituent represented by RO-, and R represents aryl having 5 to 60 carbon atoms. Examples of such aryloxy include phenyloxy, naphthyloxy, diphenyloxy and the like.

The alkyloxy in the present invention is a monovalent substituent group represented by R'O-, wherein R 'is an alkyl having 1 to 40 carbon atoms and includes a linear, branched or cyclic structure . Examples of such alkyloxy include methoxy, ethoxy, n-propoxy, 1-propoxy, t-butoxy, n-butoxy, pentoxy and the like.

The arylamine in the present invention means an amine substituted with aryl having 6 to 60 carbon atoms.

The cycloalkyl in the present invention means a monovalent substituent derived from a monocyclic or polycyclic non-aromatic hydrocarbon having 3 to 40 carbon atoms. Examples of such cycloalkyls include cyclopropyl, cyclopentyl, cyclohexyl, norbornyl, adamantine, and the like.

Heterocycloalkyl in the present invention means a monovalent substituent derived from a non-aromatic hydrocarbon having 3 to 40 nuclear atoms, wherein at least one carbon of the ring, preferably 1 to 3 carbons, is N, O, S or Se. &Lt; / RTI &gt; Examples of such heterocycloalkyl include morpholine, piperazine and the like.

The alkylsilyl in the present invention is silyl substituted with alkyl having 1 to 40 carbon atoms, and arylsilyl means silyl substituted with aryl having 5 to 40 carbon atoms.

The condensed ring in the present invention means a condensed aliphatic ring, a condensed aromatic ring, a condensed heteroaliphatic ring, a condensed heteroaromatic ring, or a combination thereof.

In the present invention, the mixing ratio of the two or more kinds of bipolar compounds having different electron mobility when producing the life improving layer 304 is not particularly limited. In one example, the two bipolar compounds may be mixed in a ratio of 1:99 to 99: 1, and preferably in the range of 10:90 to 90:10. The method for manufacturing the life improving layer 304 is not particularly limited as long as it is a method known in the art. For example, the method can be manufactured by the following two methods.

The first method is a co-deposition method in which two different bipolar compounds are respectively placed in a first heat source and a second heat source, and at the same time heat is applied to form the life improving layer 304.

More specifically, the evaporation rate per second of the first heat source and the second heat source is controlled at a degree of vacuum of 1 x 10 ^-06 torr or less to co-deposit at an appropriate ratio. At this time, the amounts of the respective bipolar compounds located in the first heat source and the second heat source are not particularly limited.

In the second method, the number of the heat sources to be used is reduced and the bipolar compounds used for forming the life improving layer 304 are mixed at a proper ratio to simplify the formation process, (304). &Lt; / RTI &gt;

More specifically, a method for forming a lifetime improving layer 304 by placing a bipolar compound mixed in a first heat source at a degree of vacuum of 1 x 10 ^-6 or less. This method reduces errors in the mixing ratio, The light emitting layer can be formed. The amount of each bipolar compound to be used at this time is not particularly limited.

The electron transporting layer 305 and the electron injection layer 306 included in the organic material layer 300 of the present invention serve to transfer electrons injected from the cathode 200 to the light emitting layer 303.

The material constituting the electron transport layer 305 and the electron injection layer 306 is not particularly limited as long as it is a material which can easily inject electrons and has a high electron mobility. Non-limiting examples of the material include a bipolar compound, an anthracene derivative, a heteroaromatic compound , Alkali metal complex compounds, and the like.

More specifically, the electron transport layer 305 and / or the electron injection layer 306 of the present invention may use the same bipolar material as the life improving layer 304. The electron transport layer 305 and / or the electron injection layer 306 may be formed by co-depositing an alkali metal complex so as to facilitate the injection of electrons from the cathode. Examples of the alkali metal complex compound include an alkali metal, an alkaline earth metal, and a rare earth metal.

The organic layer 300 of the present invention may further include an organic layer (not shown) blocking electrons and excitons between the hole transport layer 302 and the emission layer 303.

This organic film layer has a high LUMO value to prevent electrons from migrating to the hole transport layer 302 and to prevent the excitons of the emission layer 303 from diffusing into the hole transport layer 302 due to high triplet energy. The material forming the organic film layer is not particularly limited, and examples thereof include carbazole derivatives and arylamine derivatives.

The method for producing the organic material layer 300 of the present invention is not particularly limited, and examples thereof include a vacuum deposition method and a solution coating method. Examples of the solution coating method include a spin coating method, a dip coating method, a doctor blading method, an ink jet printing method, a thermal transfer method, and the like.

The organic electroluminescent device of the present invention has a structure in which an anode 100, an organic layer 300 and a cathode 200 are sequentially stacked. The organic electroluminescent device of the present invention has a structure in which an anode 100, an organic layer 300, An insulating layer or an adhesive layer may be further included between the first electrode layer 300 and the second electrode layer 300. In the organic electroluminescent device of the present invention, lifetime characteristics can be excellent because the lifetime of initial brightness is increased while maintaining the maximum luminous efficiency when voltage and current are applied.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the present invention is not limited by the following Examples.

[Preparation Examples 1 to 36] Preparation of compounds LE-01 to LE-16

To a bipolar compound of the present invention were prepared a compound represented by the LE-LE-01 to 16, ΔEst, a triplet energy, the ionization potential, E to respectively measured by methods known in the art, the _{HOMO LUMO} -E Table 1 Respectively.

The working compounds LE-01 to LE-16 of the present invention are shown below.

Calculated value (B3LYP / 6-31G *) Actual value Bipolar compound ΔEst
(S1-T1) Triplet energy Ionization potential E _HOMO -E _LUMO LE-01 0.059 2.53 5.6 3.37 LE-02 0.138 2.65 5.58 3.43 LE-03 0.177 2.50 5.64 3.07 LE-04 0.202 2.57 5.75 3.27 LE-05 0.058 2.39 5.54 3.55 LE-06 0.261 2.81 5.82 3.36 LE-07 0.340 2.78 5.78 3.23 LE-08 0.129 2.57 5.70 2.93 LE-09 0.201 2.43 5.61 3.45 LE-10 0.348 2.39 5.91 3.26 LE-11 0.310 2.52 5.97 3.33 LE-12 0.044 2.47 5.69 3.06 LE-13 0.180 2.40 5.78 3.13 LE-14 0.298 2.74 6.01 3.33 LE-15 0.057 2.50 6.01 3.33 LE-16 0.157 2.43 5.99 3.10

Relative electron mobility of LE-01, LE-06, LE-08 and LE-10 among the bipolar compounds of the present invention was measured as follows.

The glass substrate coated with ITO (Indium tin oxide) thin film with thickness of 1500 Å was ultrasonically cleaned with distilled water. After the distilled water was washed, the substrate was ultrasonically cleaned with a solvent such as isopropyl alcohol, acetone, methanol, and dried. Then, the substrate was transferred to a UV OZONE cleaner (Power Sonic 405, Hoshin Tech) The substrate was transferred to an evaporator.

The device was deposited on the ITO transparent electrode (substrate) prepared as described above with the structure shown in Table 2 below, and the current density and the driving voltage were measured and shown in FIG.

compound Al LiQ LE-01, LE-06, LE-08, LE-10 LiQ Al thickness 20 nm 1 nm 100 nm 1 nm 120 nm

[Examples 1 to 20] Preparation of blue fluorescent organic electroluminescence device

The glass substrate coated with ITO (Indium tin oxide) thin film with thickness of 1500 Å was ultrasonically cleaned with distilled water. After the distilled water was washed, the substrate was ultrasonically cleaned with a solvent such as isopropyl alcohol, acetone, methanol, and dried. Then, the substrate was transferred to a UV OZONE cleaner (Power Sonic 405, Hoshin Tech) The substrate was transferred to an evaporator.

A hole injecting layer, a hole transporting layer, a light emitting layer, a lifetime improving layer, an electron transporting layer, an electron injecting layer and a cathode were sequentially deposited on the ITO transparent electrode (substrate) prepared as described above. The structure of the manufactured device is shown in Table 3 below.

compound thickness Hole injection layer DS-205 (Doosan) 80nm Hole transport layer NPB 15 nm The light- ADN + 5% DS-405 (Doosan) 30 nm Life improvement layer LE-01 to LE-36 5 nm Electron transport layer Alq ₃ 25 nm Electron injection layer LiF 1 nm cathode Al 200 nm

The structures of NPB, AND and Alq ₃ used in Table 3 are as follows.

[Comparative Example 1] Production of blue fluorescent organic electroluminescent device

A device was fabricated in the same manner as in Example 1, except that the electron transport layer was deposited at 30 nm without using the life improving layer.

[Comparative Examples 2 to 4] Preparation of blue fluorescent organic electroluminescent device

A device was fabricated in the same manner as in Example 1 except that BCP, LE-08, and LE-10 were used for the life improving layer, respectively.

[Experimental Example 1]

The driving voltage, current efficiency, light emitting wavelength and lifetime (T ₉₇ ) at a current density of 10 mA / cm ² were measured for each of the devices manufactured in Examples 1 to 20 and Comparative Examples 1 to 4, Table 4 shows the results.

Life improvement layer
compound Driving voltage
(V) Current efficiency
(cd / A) Emission peak
(nm) life span
(hr) Example 1 LE-01 + LE-08 (5: 5) 4.2 6.3 458 60 Example 2 LE-02 + LE-08 (5: 5) 4.5 6.6 458 58 Example 3 LE-03 + LE-08 (5: 5) 4.7 6.7 458 80 Example 4 LE-04 + LE-08 (5: 5) 4.2 6.8 458 82 Example 5 LE-05 + LE-08 (5: 5) 4.5 6.6 458 59 Example 6 LE-06 + LE-08 (5: 5) 4.3 6.8 458 103 Example 7 LE-07 + LE-08 (5: 5) 4.2 6.7 458 89 Example 8 LE-09 + LE-08 (5: 5) 4.7 6.7 457 62 Example 9 LE-10 + LE-08 (5: 5) 4.4 7.1 458 109 Example 10 LE-11 + LE-08 (5: 5) 4.1 6.7 458 60 Example 11 LE-12 + LE-08 (5: 5) 4.9 6.8 458 61 Example 12 LE-13 + LE-08 (5: 5) 5.0 6.6 458 64 Example 13 LE-14 + LE-08 (5: 5) 5.0 6.4 458 84 Example 14 LE-15 + LE-08 (5: 5) 4.9 7.0 458 88 Example 15 LE-16 + LE-08 (5: 5) 4.2 6.5 458 81 Example 16 LE-01 + LE-10 (5: 5) 4.6 6.9 458 57 Example 17 LE-06 + LE-10 (5: 5) 4.5 6.6 458 103 Example 18 LE-01 + LE-06 (5: 5) 4.3 6.5 458 100 Example 19 LE-10 + LE-08 (8: 2) 4.8 7.1 458 105 Example 20 LE-10 + LE-08 (2: 8) 4.5 7.0 458 107 Comparative Example 1 - 4.7 5.6 458 32 Comparative Example 2 BCP 5.3 5.9 458 28 Comparative Example 3 LE-01 4.2 6.0 458 54 Comparative Example 4 LE-08 4.2 6.6 458 55 The life span is measured by the lifetime meter to measure the luminous intensity to 97%.

As shown in Table 4, the organic electroluminescent devices of Examples 1 to 20 of the present invention in which two or more kinds of bipolar compounds having different electron mobility are included as the lifetime improving layer are superior to the organic electroluminescent devices of Comparative Examples 1 to 4 It was confirmed that the efficiency and the lifetime were excellent. In particular, it was confirmed that the organic electroluminescent device of the present invention has an improved lifetime as compared with Comparative Examples 3 to 4 in which one type of bipolar compound is used as the life improving layer.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Claims (20)

anode;
cathode; And
Wherein at least one organic material layer selected from the group consisting of a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer and an electron injecting layer is provided between the anode and the cathode,
An organic electroluminescent device further comprising a lifetime enhancement layer (LEL) between the light emitting layer and the electron transporting layer,
The lifetime improving layer is composed of a first bipolar compound having a different electron mobility and a second bipolar compound having both an electron attracting group (EWG) having a large electron absorbing property and an electron donating group (EDG) ) Compound,
An electron withdrawing group (EWG) moiety each of which comprises the first amphipatic compound and the second amphipatic compound comprises one of the moieties represented by the following formula,

Wherein the electron donor group (EDG) moiety included in each of the first and second amphiphilic compounds comprises one of the moieties represented by the following formulas (1a) to (1n)
[Formula 1a]

[Chemical Formula 1b]

[Chemical Formula 1c]

&Lt; RTI ID = 0.0 &

[Formula 1e]

(1f)

[Formula 1g]

[Chemical Formula 1h]

[Formula 1i]

[Chemical Formula 1j]

[Chemical Formula 1k]

&Lt; EMI ID =

[Formula 1m]

[Formula 1n]

In the above general formulas (1a) to (1n)
X ₁ and X ₄ are each independently selected from the group consisting of O, S, and N (Ar ₁ ), wherein the plurality of Ar _{1 s} are the same or different,
Y ₁ to Y ₄ are the same or different and each independently N or C (R ₁ ), wherein a plurality of R _{1 s} are the same or different,
X ₂ and X ₃ are the same or different and each independently N or C (R ₂ ), wherein the plurality of R _{2 s} are the same or different,
Y ₅ to Y ₁₄ are the same or different and each independently N or C (R ₃ ), wherein the plurality of R _{3 s} are the same or different,
R ₁ to R ₃ are the same or different and each independently represent a group consisting of hydrogen, deuterium, a C ₁ to C ₄₀ alkyl group, a C ₆ to C ₆₀ aryl group, and a heteroaryl group having 5 to 60 nuclear atoms Lt; / RTI &gt;
Ar ₁ is independently selected from the group consisting of a C ₆ to C ₆₀ aryl group and a heteroaryl group having 5 to 60 nuclear atoms,
The alkyl, aryl and heteroaryl groups of R ₁ to R ₃ and Ar ₁ are each independently at least one member selected from the group consisting of deuterium, a C ₆ to C ₄₀ aryl group, and a heteroaryl group having 5 to 40 nuclear atoms Substituted or unsubstituted;
Wherein the first amphipatic compound and the second amphipatic compound satisfy the following conditions (i) to (iv), respectively, and they are mixed at a ratio of 1:99 to 99: 1:
(i) the ionization potential [Ip (LEL)] is 5.5 eV or more,
(Ii) E _HOMO -E _LUMO &gt; 2.9 eV,
(Iii) the triplet energy is greater than or equal to 2.3 eV,
(Iv) ΔEst <0.5 eV (ΔEst represents the difference between singlet energy and triplet energy of the compound) The organic electroluminescent device according to claim 1, wherein when the light emitting layer is a blue fluorescent light, a green fluorescent light, or a red phosphorescent light, the triplet energies of the two or more bipolar compounds contained in the lifetime improving layer are respectively 2.3 eV or more. The organic electroluminescent device according to claim 1, wherein when the light emitting layer is a green phosphorescent phosphor, each of the two or more bipolar compounds contained in the lifetime improving layer has a triplet energy of 2.5 eV or more and an ionization potential of 6.0 eV or more, . The organic electroluminescent device according to claim 1, wherein when the light emitting layer is a blue phosphorescent light, the two or more kinds of bipolar compounds contained in the lifetime improving layer each have a triplet energy of 2.7 eV or more and an ionization potential of 6.0 eV or more, . The organic electroluminescent device according to claim 1, wherein the electron mobility and the hole mobility of the two or more kinds of bipolar compounds contained in the lifetime enhancing layer are at least 1 × 10 ^-6 cm ² / V · s at room temperature, device. delete delete delete delete delete delete delete The organic electroluminescent device according to claim 1, wherein the electron transport layer and the compound included in the lifetime enhancing layer are the same. The organic electroluminescent device according to claim 1, wherein the electron injecting layer and the compound included in the lifetime enhancing layer are the same. The organic electroluminescent device according to claim 1, wherein the electron injection layer or the electron transport layer is formed by co-deposition of an alkali metal complex. The organic electroluminescent device of claim 1, further comprising an organic layer between the hole transport layer and the light emitting layer to block electrons and excitons. The organic electroluminescent device according to claim 1, wherein the light emitting layer comprises a host material and a dopant material, and the dopant is contained in an amount ranging from 0.1 wt% to 30 wt%. The organic electroluminescent device according to claim 1, wherein a plurality of light emitting layers are sequentially stacked between the hole transporting layer and the electron transporting layer to realize a mixed color when voltage and current are applied. The organic electroluminescence device of claim 1, wherein a plurality of light emitting layers of a single material are stacked between the hole transporting layer and the electron transporting layer, or a plurality of light emitting layers of different materials are provided in series, Type organic electroluminescent device. The organic electroluminescent device according to claim 1, wherein, when a voltage, a current, or both are applied, the lifetime of the initial brightness is increased while maintaining the maximum luminous efficiency.

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