An electron transport material, an OLED having the material, and an organic light emitting device

Abstract

The present application relates to the technical field of organic photoelectric material preparation, and particularly relates to an electron transport material, an OLED with the material and an organic light-emitting device. The electron transport material is prepared by taking triazine group as a framework, taking phenyl and cyano-substituted biphenyl as specific substituent groups, and limiting the combination of methyl, adamantyl, phenyl and pyridyl, and the electron transport material is used as a material for constituting an electron transport layer to prepare an organic electroluminescent device, so that the evaporation process of the device can be smoothly performed, the luminous efficiency of the organic light-emitting device is effectively improved, and the electron transport material has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic photoelectric material preparation, and particularly relates to an electron transport material, an OLED with the material and an organic light-emitting device. BACKGROUND

[0002] An organic electroluminescent diode (OLED) is also called an organic electroluminescent device, which is a technology of converting electrical energy into light energy through organic light-emitting materials by applying a voltage to an organic electroluminescent element to inject holes from an anode and electrons from a cathode into a light-emitting layer, and then recombine the injected holes and electrons to form excitons to cause light emission.

[0003] An electron transport layer can transport “electrons” from a cathode to a light-emitting layer, and is a key component of the basic structure of an OLED. At present, the existing electron transport layer materials still have some problems in device application, for example, some organic electron transport materials are prone to aging and decomposition, which reduces the electron transport efficiency and affects the normal operation of the electronic device. In addition, existing research shows that a mixed electron transport layer can enhance electron injection and input, but some existing organic electron transport materials do not have excellent doping effect with Liq materials, and cannot well improve the device efficiency.

[0004] Therefore, it is necessary to develop an electron transport layer material with good evaporation stability and wide application, and to find a suitable OLED optoelectronic functional material for an OLED device to solve the above problems. SUMMARY

[0005] In order to solve the above technical problems, the present application provides an electron transport material, an OLED with the material and a display or lighting device. The provided electron transport material is structured by triazine group, phenyl and cyano-substituted biphenyl as specific substituent groups, and limited to methyl, adamantyl, phenyl and pyridyl for matching, so that the electron transport material can maintain high stability in the evaporation process, and at the same time, the device can have high efficiency.

[0006] The present application provides an electron transport material, which is realized by the following technical scheme:

[0007] An electron transport material has a structure shown in formula I:

[0008] ;

[0009] R1, R2are each independently selected from the group consisting of cyano-substituted or unsubstituted C6-C36aryl; R3is independently selected from the group consisting of C3-C12cycloalkyl, substituted or unsubstituted C6-C36aryl; when R3contains a substitution, the substitution is selected from one or more of deuterium, cyano, C1-C12alkyl, C3-C12cycloalkyl, C5-C36heteroaryl; R 12 -R 15 R1, R2are each independently selected from the group consisting of cyano-substituted or unsubstituted C6-C36aryl; R3is independently selected from the group consisting of C3-C12cycloalkyl, substituted or unsubstituted C6-C36aryl; when R3contains a substitution, the substitution is selected from one or more of deuterium, cyano, C1-C12alkyl, C3-C12cycloalkyl, C5-C36heteroaryl; R 12 -R 15 at least one of the substituents is cyano.

[0010] R1, R2are each independently selected from the group consisting of cyano-substituted or unsubstituted C6-C36aryl; R3is independently selected from the group consisting of C3-C12cycloalkyl, substituted or unsubstituted C6-C36aryl; when R3contains a substitution, the substitution is selected from one or more of deuterium, cyano, C1-C12alkyl, C3-C12cycloalkyl, C5-C36heteroaryl; R 12 -R 15 R1, R2are each independently selected from the group consisting of cyano-substituted or unsubstituted C6-C36aryl; R3is independently selected from the group consisting of C3-C12cycloalkyl, substituted or unsubstituted C6-C36aryl; when R3contains a substitution, the substitution is selected from one or more of deuterium, cyano, C1-C12alkyl, C3-C12cycloalkyl, C5-C36heteroaryl; R 12 -R 15 at least one of the substituents is cyano.

[0011] R1, R2are each independently selected from the group consisting of cyano-substituted or unsubstituted C6-C36aryl; R3is independently selected from the group consisting of C3-C12cycloalkyl, substituted or unsubstituted C6-C36aryl; when R3contains a substitution, the substitution is selected from one or more of deuterium, cyano, C1-C12alkyl, C3-C12cycloalkyl, C5-C36heteroaryl; R 12 -R 15 R1, R2are each independently selected from the group consisting of cyano-substituted or unsubstituted C6-C36aryl; R3is independently selected from the group consisting of C3-C12cycloalkyl, substituted or unsubstituted C6-C36aryl; when R3contains a substitution, the substitution is selected from one or more of deuterium, cyano, C1-C12alkyl, C3-C12cycloalkyl, C5-C36heteroaryl; R 12 -R 15 R1, R2are each independently selected from the group consisting of cyano-substituted or unsubstituted C6-C36aryl; R3is independently selected from the group consisting of C3-C12cycloalkyl, substituted or unsubstituted C6-C36aryl; when R3contains a substitution, the substitution is selected from one or more of deuterium, cyano, C1-C12alkyl, C3-C12cycloalkyl, C5-C36heteroaryl; R

[0012] Preferably, the hydrogen atoms in the formula I can be partially or fully deuterated.

[0013] According to one or more embodiments, the present application provides an electron transport material selected from any one of the following chemical structures, wherein "CN" represents cyano, "Ad" represents adamantyl, and "D" represents deuterium:

[0014]

[0015] The present application also provides an application in an organic electroluminescent device as described above.

[0016] The present application also provides an organic electroluminescent device, which comprises:

[0017] a substrate layer;

[0018] a first electrode on the substrate;

[0019] an organic light-emitting functional layer on the first electrode;

[0020] a second electrode on the organic light-emitting functional layer;

[0021] The organic light-emitting functional layer comprises an electron transport layer, which comprises the electron transport material as described above.

[0022] The present application also provides a composition, which comprises the electron transport material as described in formula (I).

[0023] The present application also provides a preparation, which comprises the electron transport material as described in formula (I) above or the composition as described above and at least one solvent. The solvent is not particularly limited, and the solvents well known to those skilled in the art such as unsaturated hydrocarbon solvents such as toluene, xylene, mesitylene, tetralin, decalin, bicyclohexane, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, halogenated saturated hydrocarbon solvents such as carbon tetrachloride, chloroform, dichloromethane, dichloroethane, chlorobutane, bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane, bromocyclohexane, halogenated unsaturated hydrocarbon solvents such as chlorobenzene, dichlorobenzene, trichlorobenzene, ether solvents such as tetrahydrofuran, tetrahydropyran, ester solvents such as benzoic acid alkyl ester, and the like can be used.

[0024] The organic electroluminescent device of the present application can be used in an OLED lighting or display device.

[0025] The present application also provides a display or lighting device, which comprises one or more of the organic electroluminescent devices as described above.

[0026] In summary, compared with the prior art, the present application has the following beneficial effects:

[0027] The electronic transport material of the present application, by taking triazine group as the framework, phenyl, cyano-substituted biphenyl as specific substituent group, and limiting methyl, adamantyl, phenyl, pyridyl for collocation, so that the compound has excellent luminous efficiency and better stability; meanwhile, the electronic transport material provided by the present application is used in devices, can effectively cooperate with other layer materials of the device for transmission and light emission, and improves the light emission efficiency of the organic light emitting device. DETAILED DESCRIPTION

[0028] The technical solutions of the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0029] Throughout the specification, unless explicitly described otherwise, any component "comprising" any component will be understood to implicitly include other elements, rather than excluding any other elements. In addition, it should be understood that throughout the specification, when an element such as a layer, film, region or substrate is referred to as "on" or "above" another element, it can be "directly on" the other element, or there can be an intermediate element. In addition, "on" or "above" refers to being above the target portion, and does not necessarily refer to being above in the direction of gravity.

[0030] An object of the present application is to provide an organic electroluminescent device, comprising: a substrate layer; a first electrode on the substrate; an organic light-emitting functional layer on the first electrode; a second electrode on the organic light-emitting functional layer; the organic light-emitting functional layer comprises an electron transport layer; the electron transport layer comprises an electron transport material comprising a triazine group.

[0031] In one embodiment of the present application, the electron transport layer in an organic electroluminescent (OLED) device comprises one or more components of the compounds as shown in the general formula I above as an electron transport material.

[0032] In a preferred embodiment of the present application, an OLED is provided, comprising a substrate, an anode, a cathode, an organic light-emitting functional layer, a cover layer, wherein the organic light-emitting functional layer can comprise a light-emitting layer, a hole transport layer, a hole injection layer, an electron transport layer, an electron injection layer, etc., and can only comprise a light-emitting layer and one or more other layers; wherein the electron transport layer comprises one or more components of the compounds as shown in the general formula I above. Optionally, there is a cover layer, a protective layer and / or an encapsulation layer on the cathode.

[0033] The substrate described in the present application can use any substrate used in a typical organic light emitting device. It can be a glass or transparent plastic substrate, or a substrate of non-transparent material such as silicon or stainless steel, or a flexible PI film. Different substrates have different mechanical strength, thermal stability, transparency, surface smoothness, and water resistance. Depending on the properties of the substrate, the use direction is different.

[0034] As the material of the hole injection layer, the hole transport layer, and the electron injection layer, any material can be selected from the known related materials for OLED devices.

[0035] As the host-guest material capable of generating blue fluorescence, green fluorescence, and blue-green fluorescence, it not only needs to have extremely high fluorescence quantum yield efficiency, but also needs to have appropriate energy levels.

[0036] The present application will be specifically described below in combination with specific examples. All raw materials and solvents in the synthesis examples are commercially available unless otherwise specified. The solvents are used directly without further treatment.

[0037] Examples

[0038] Example 1: Synthesis of compound 1

[0039] Synthesis route:

[0040]

[0041] Synthesis method:

[0042] 1) In a 1L three-necked flask, first put SM1 (1mmol), SM2 (1mmol), NaHCO3 (3mmol), toluene 100mL, ethanol 50mL, water 100mL, then add Pd(dppf)Cl2 (0.05mmol), and replace three times with nitrogen; warm to reflux for 5.5h; add 500mL water to the reaction liquid and stir, stand to separate, wash the toluene phase with water twice, and saturated brine once, dry with anhydrous sodium sulfate, and filter. Reduce pressure with an oil pump and fractionate, to obtain intermediate S1 at 118-125 degrees;

[0043] 2) In a washed and dried 1L three-necked flask, first put in S1 (1 mmol), toluene 200 ml, KOAc (3 mmol), replace with nitrogen three times, then reflux to remove water, about 50 ml of solvent is removed after refluxing for half an hour, stop heating, and then add B2(Pin)2 (1.5 mmol), Pd(dppf)Cl2 (0.05 mmol), heat and reflux for 2 hours; while hot, pass through a short column, wash with 500 ml of toluene, add 200 ml of petroleum ether PE and shake overnight, filter and dry to obtain a white solid S2;

[0044] 3) In a washed and dried 1L three-necked flask, put in S2 (1 mmol), SM4 (1 mmol), K2CO3 (3 mmol), toluene 100 ml, THF 50 ml, water 100 ml, and finally add Pd(dppf)Cl2 (0.05 mmol), replace with nitrogen three times; after refluxing for 2.5 hours, add 100 ml of water, shake for 10 minutes, and filter. After filtering, put in a blast drying oven at 65 degrees overnight to obtain a crude product, which is dissolved in xylene, passed through silica gel, and washed with xylene to obtain a white solid S3;

[0045] 4) In a washed and dried 1L three-necked flask (mechanical stirring), put in S3 (1 mmol), SM5 (1 mmol), K2CO3 (3 mmol), 1,4-dioxane 300 ml, water 60 ml, and finally add Pd2dba3 (0.05 mmol), X-Phos (0.1 mmol), replace with nitrogen three times; after refluxing for 3.5 hours, add 150 ml of water, shake, filter, and purify by column chromatography, wash the column with petroleum ether / dichloroethane (PE / DCM=2), and put in a blast drying oven at 60 degrees overnight to obtain the final product, a white solid - compound 1;

[0046] Test the structure of target compound 1: LC-MS (m / z): the theoretical value is 562.22, and the test value is 562.46.

[0047] Example 2: Synthesis of compound 8

[0048] The difference from example 1 is that the reactant SM2 is adjusted to , and compound 8 is synthesized according to the synthesis steps and reaction conditions of example 1. LC-MS (m / z): the theoretical value is 772.36, and the test value is 772.82.

[0049] Example 3: Synthesis of compound 12

[0050] The difference from Example 1 is that the reactant SM2 is adjusted to The difference from Example 1 is that the reactant SM5 is adjusted to Compound 12 is synthesized according to the synthetic steps and reaction conditions of Example 1, and analyzed by liquid chromatography-mass spectrometry to obtain LC-MS (m / z): the theoretical value is 639.24, and the tested value is 639.52.

[0051] Example 4: Synthesis of compound 15

[0052] The difference from Example 1 is that the reactant SM2 is adjusted to The difference from Example 1 is that the reactant SM5 is adjusted to Compound 15 is synthesized according to the synthetic steps and reaction conditions of Example 1, and analyzed by liquid chromatography-mass spectrometry to obtain LC-MS (m / z): the theoretical value is 714.28, and the tested value is 714.62.

[0053] Example 5: Synthesis of compound 18

[0054] The difference from Example 1 is that the reactant SM2 is adjusted to The difference from Example 1 is that the reactant SM5 is adjusted to Compound 18 is synthesized according to the synthetic steps and reaction conditions of Example 1, and analyzed by liquid chromatography-mass spectrometry to obtain LC-MS (m / z): the theoretical value is 714.28, and the tested value is 714.63.

[0055] Example 6: Synthesis of compound 32

[0056] The difference from Example 1 is that the reactant SM2 is adjusted to The difference from Example 1 is that the reactant SM4 is adjusted to Compound 32 is synthesized according to the synthetic steps and reaction conditions of Example 1, and analyzed by liquid chromatography-mass spectrometry to obtain LC-MS (m / z): the theoretical value is 689.26, and the tested value is 689.60.

[0057] Example 7: Synthesis of compound 43

[0058] ;

[0059] 1) In a washed and dried 1L three-necked flask, first put in SM1-43 (1 mmol), toluene 200 ml, KOAc (3 mmol), replace with nitrogen for three times, then reflux to remove water, about 50 ml solvent is removed after refluxing for half an hour, stop heating, and then add B2(Pin)2 (1.5 mmol), Pd(dppf)Cl2 (0.05 mmol), heat and reflux for 2 hours; while hot, pass through a short column, wash with 500 ml of toluene, add 200 ml of petroleum ether PE to make a slurry overnight, filter and dry to obtain a white solid S1-43;

[0060] 2) In a washed and dried 1L three-necked flask, put in S1-43 (1 mmol), SM2-43 (1 mmol), K2CO3 (3 mmol), toluene 100 ml, THF 50 ml, water 100 ml, and finally add Pd(dppf)Cl2 (0.05 mmol), replace with nitrogen for three times; after refluxing for 2.5 hours, cool down, add 100 ml of water, make a slurry for 10 minutes, and filter. After filtering, put in a blast drying oven at 65 degrees overnight to obtain a crude product, which is dissolved in xylene, passed through silica gel, and washed with xylene to obtain a white solid S2-43;

[0061] 3) In a washed and dried 1L three-necked flask, mechanically stir, put in S2-43 (1 mmol), SM3-43 (1 mmol), K2CO3 (3 mmol), 1,4-dioxane 300 ml, water 60 ml, and finally add Pd2dba3 (0.05 mmol), X-Phos (0.1 mmol), replace with nitrogen for three times; after refluxing for 3.5 hours, cool down, add 150 ml of water, make a slurry, filter, and purify by column chromatography, wash the column with petroleum ether / dichloroethane (PE / DCM=2), and put in a blast drying oven at 60 degrees overnight to obtain the final product 43;

[0062] LC-MS (m / z): the theoretical value is 797.35, and the test value is 797.83, by liquid chromatography-mass spectrometry analysis.

[0063] Example 8: synthesis of compound 57

[0064] The difference from example 1 is that the reactant SM4 is adjusted to , and the reactant SM5 is adjusted to , and compound 57 is synthesized by referring to the synthesis steps and reaction conditions of example 1. LC-MS (m / z): the theoretical value is 714.28, and the test value is 714.60, by liquid chromatography-mass spectrometry analysis.

[0065] Example 9: synthesis of compound 64

[0066] The difference from Example 1 is that the adjusted reactant SM2 is The difference from Example 1 is that the adjusted reactant SM4 is The difference from Example 1 is that the adjusted reactant SM5 is According to the synthetic steps and reaction conditions of Reference Example 1, compound 64 is synthesized. LC-MS (m / z) analysis by liquid chromatography-mass spectrometry gives a theoretical value of 731.31 and a test value of 731.70.

[0067] Example 10: Synthesis of compound 65

[0068] According to the synthetic steps and reaction conditions of Reference Example 7 for compound 43, SM2-43 is adjusted to SM3-43 is adjusted to Compound 65 is synthesized. LC-MS (m / z) analysis by liquid chromatography-mass spectrometry gives a theoretical value of 772.36 and a test value of 772.82.

[0069] Example 11: Synthesis of compound 69

[0070] The difference from Example 1 is that the adjusted reactant SM4 is According to the synthetic steps and reaction conditions of Reference Example 1, compound 69 is synthesized. LC-MS (m / z) analysis by liquid chromatography-mass spectrometry gives a theoretical value of 714.28 and a test value of 714.62.

[0071] Example 12: Synthesis of compound 70

[0072] The difference from Example 1 is that the adjusted reactant SM2 is The difference from Example 1 is that the adjusted reactant SM4 is According to the synthetic steps and reaction conditions of Reference Example 1, compound 70 is synthesized. LC-MS (m / z) analysis by liquid chromatography-mass spectrometry gives a theoretical value of 848.39 and a test value of 848.95.

[0073] The following are several application examples of the electronic transport material described in the present application applied in OLED devices to further illustrate the beneficial effects of the compounds of the present application. The materials used in the examples are commercially available or synthesized by the applicant.

[0074] Manufacture of OLED device:

[0075] As a reference preparation mode of a device embodiment, the present application evaporates 50-500 nm of ITO / Ag / ITO (weight ratio of ITO:Ag:ITO is 1:(10-20):1) on an alkali-free glass substrate as an anode, and then evaporates a hole injection layer (5-20 nm), a hole transport layer (50-120 nm), a light-emitting auxiliary layer (5-120 nm), a light-emitting layer (host material:doping material, doping material weight ratio 0.5%-10%, 20-50 nm), a hole blocking layer (5-20 nm), an electron transport layer (20-80 nm), and an electron injection layer (0.5-10 nm) in sequence on the anode, co-evaporates Mg and Ag (weight ratio 1:9, 10-50 nm) to form a semi-transparent cathode, and then evaporates a cover layer compound (50-90 nm). Finally, the light-emitting device is packaged with an epoxy resin adhesive in a nitrogen atmosphere.

[0076] In a preferred embodiment, the structure of the OLED device provided by the present application is as follows: first, the alkali-free glass substrate is washed with isopropyl alcohol for 15 minutes using an ultrasonic cleaner, and then subjected to UV ozone washing treatment in air for 30 minutes. The treated substrate is evaporated by vacuum evaporation method, first evaporating ITO / Ag / ITO (weight ratio of ITO:Ag:ITO is 1:10:1, 120 nm) as an anode, and then evaporating a hole injection layer (HT:PD weight ratio=98:2, 10 nm), a hole transport layer (HT, 100 nm), a light-emitting auxiliary layer (BP, 5 nm), a light-emitting layer (host material BH:doping material weight ratio=97:3, 30 nm), a hole blocking layer (HBL, 5 nm), an electron transport layer (compound 1:Liq=1:1, 30 nm), and an electron injection layer (Yb, 1 nm) in sequence on the anode, co-evaporating Mg and Ag (weight ratio 1:9, 10 nm) to form a semi-transparent cathode, and then evaporating compound CPL (65 nm) as a cover layer. This is referred to as Application Example 1.

[0077] It should be noted that the other layer materials used in this application example are only exemplary and are not a special limitation of the application of the electron transport layer material in the device. Conventional replacement can be selected from known or unknown materials. The molecular structure of the related materials is shown below (particularly preferably selected from the following structures, but not limited to the following structures):

[0078] .

[0079] Application Examples 2-11 and Comparative Example 1 were prepared according to the method provided in Application Example 1 above, with the only difference being that the compounds listed in Table 1 were used as the electron transport material instead of Compound 1 in Application Example 1. The structures of Ref-1 to Ref-3 used in Comparative Examples 1-3 are as follows:

[0080] Performance evaluation of OLED devices:

[0081] The current of the OLED device at different voltages was tested using a Keithley 2365A digital nanovoltmeter, and then the current was divided by the light-emitting area to obtain the current density of the OLED device at different voltages; the luminance and radiant flux density of the OLED device at different voltages were tested using a Konicaminolta CS-2000 spectroradiometric luminance meter; according to the current density and luminance of the OLED device at different voltages, the operating voltage Volt and current efficiency (cd / A) at the same current density (10 mA / cm 2 ) were obtained, and the Blue Index in the blue light, which is also a parameter for measuring the luminous efficiency of the blue light, E refers to the current efficiency, and CIEy refers to the ordinate color point obtained by inputting the half-peak width wavelength of the light emitted by the device into the CIE1930 software; LT95 refers to the time required for the luminance of the OLED material to decay to 95% of the initial luminance, which is a key indicator for measuring the stability and lifetime of the OLED material. The test data are shown in Table 1.

[0082] Table 1. Application Example device and electron emission characteristics of the electron transport layer material

[0083]

[0084] As can be seen from Table 1, the performance of the material of the application examples is directly compared with the performance of the materials of Ref-1 to Ref-3 of the comparative examples. The cyano group is introduced on the basis of the comparison of the electron transport materials to optimize the performance of the display panel. By using a specific electron transport material, the overall performance of the display panel is improved. The electron transport material of the application combines a triazine group with a phenyl group, an alkyl group, and an adamantane group, and has good thermal stability. At the same time, the introduction of the cyano group will cause the intrinsic dipole moment of the material to increase, which will improve the effect of the electron transport material and the Liq (8-hydroxyquinoline lithium) material doping, thereby effectively improving the electron mobility of the material, better realizing the balance of electron and hole transport, improving the luminous efficiency of the device, reducing the power consumption of the white light device, and having unexpected technical effects. In addition, it should be noted that, in order to further meet the requirements of the core display indicators of the photoelectric performance of the device, the structure of each layer of the device in the application is optimized, which belongs to a low-voltage and high-efficiency device system, and the lifetime is slightly shorter, but still meets the industry standard level of organic optoelectronic device applications.

[0085] The specific embodiments are only illustrative of the present application, and are not intended to limit the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, and the modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An electron transport material, characterized by, having the structure of Formula I: In the formula I, R1, R2are each independently selected from phenyl, naphthyl, biphenyl; R3is independently selected from adamantyl, substituted or unsubstituted phenyl, biphenyl, terphenyl, when R3is substituted, the substitution is selected from one or more of deuterium, cyano, methyl, ethyl, propyl, t-butyl, adamantyl, pyridyl; R 12 -R 15 are each, on each occurrence, independently selected from hydrogen, deuterium, cyano, phenyl; and the R 12 -R 15 at least one of the substituents is cyano; and the hydrogen atoms in the formula I can be partially or fully deuterated.

2. The electron transport material according to claim 1, characterized in that, said R 12 -R 15 one of which is optionally selected from cyano and the others are optionally selected from hydrogen; or R 12 -R 15 one of which is optionally selected from cyano and the others are optionally selected from hydrogen.

3. The electron transport material according to claim 1, wherein The electron transport material is selected from any one of the following chemical structures, wherein "CN" represents a cyano group, and "D" represents deuterium:

4. Use of the electron transport material according to any one of claims 1-3 in the preparation of an organic electroluminescent device.

5. An organic electroluminescent device, characterized by The organic electroluminescent device comprises: a substrate layer; a first electrode on the substrate; an organic light-emitting functional layer on the first electrode; a second electrode on the organic light-emitting functional layer; The organic light-emitting functional layer comprises an electron transport layer comprising the electron transport material according to any one of claims 1-3.

6. A composition characterized in that, The composition comprises the electron transport material according to any one of claims 1-3.

7. A formulation characterized in that, The preparation comprises the electron transport material according to any one of claims 1-3 or comprises the composition according to claim 6 and at least one solvent.

8. A display or illumination device, characterized in that The device comprises the organic electroluminescent device according to claim 5.

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