Electron transport layer compound and preparation method thereof

Abstract

The invention discloses an electron transport layer compound and a preparation method thereof, the molecular structure general formula of the electron transport layer compound is represented by a chemical formula 1, the electron transport layer compound can be used as an electron transport layer material, and a prepared OLED device has the characteristics of low driving voltage, high luminous efficiency and long service life.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic optoelectronic materials, and more particularly relates to an electron transport layer compound, a preparation method thereof, and an organic electroluminescent device prepared by using the compound as an electron transport layer material. BACKGROUND

[0002] The organic material layer of an organic electroluminescent (OLED) device generally comprises multiple layers with different materials, such as a hole injection layer (HIL), a hole transport layer (HTL), an emission layer, an electron transport layer (ETL), and an electron injection layer (EIL). In an organic light-emitting element, when a voltage is applied between an anode and a cathode, holes from the anode and electrons from the cathode are injected into the organic material layer, and the generated excitons produce light with a specific wavelength when they migrate to the ground state. The research on electron transport layer materials lags behind that on hole transport layer materials, and the mobility of the hole transport layer materials has already exceeded 30 cm2 / V*s, while the mobility of the electron transport layer materials is much poorer. The structure of the electron transport type material currently used as an electron transport layer generally contains nitrogen-containing heterocyclic rings such as pyridine, pyrimidine, oxadiazole, triazole, and imidazole, and electron-withdrawing groups such as phosphorus oxy groups, which have electron transport properties. The electron transport layer also has a great impact on the service life of the device, for example, the mobility and energy band structure of the material determine the local electric field, charge carriers, and Joule heat distribution in the electron transport layer and its vicinity, thereby directly affecting the aging speed of the organic material and the device.

[0003] Therefore, in view of the above problems, it is an urgent problem for those skilled in the art to develop an electron transport material with high mobility, so that the organic electroluminescent device prepared therefrom has the performance advantages of low driving voltage, high efficiency, and long service life. SUMMARY

[0004] Therefore, the present application provides an electron transport layer compound and a preparation method thereof, which are used to produce a material for an organic electroluminescent device with low driving voltage, high luminous efficiency, and long service life.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] An electron transport layer compound, the molecular structure of which is represented by the general formula I:

[0007]

[0008] In the general formula, Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C2-C30 heteroaryl groups;

[0009] Z1, Z2, Z3are independently selected from C or N, and at least one is N. Preferably, at least two are N. Most preferably, Z1, Z2, Z3are all N;

[0010] Ar is selected from substituted or unsubstituted C6-C30 aryl or substituted or unsubstituted C5-C30 heteroaryl; Ar is fused to and rings with the adjacent benzene ring; and Ar can be fused to the 3,4- or 4,5- or 5,6- positions of the benzene ring;

[0011] The benzene ring fused to the Ar ring has the following definition for the order of the C atoms:

[0012]

[0013] R1is a substituent, the number of which is 0, 1 or 2; each independently selected from hydrogen, deuterium, tritium, -CN, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C30 heteroaryl;

[0014] Preferably, the structure of Ar together with the adjacent benzene ring in Formula 1 is selected as follows:

[0015]

[0016] L is selected from a bond, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl;

[0017] Y1-Y5are each independently selected from C, N, C-CN or C-Ar3, and at least one is N, and the other is C-CN; wherein Ar3is substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl.

[0018] Preferably, Ar3is selected from:

[0019]

[0020] Preferably, in the present application, "substituted or unsubstituted C6-C30 aryl" is each independently selected from substituted or unsubstituted phenyl, naphthyl, phenanthryl, anthryl, biphenyl, triphenylenyl, pyrenyl, spirobifluorenyl, perylenyl, indenyl, azulenyl, and benzophenanthryl.

[0021] Preferably, in the present application, "substituted or unsubstituted C3-C30 heteroaryl" is each independently selected from the group consisting of substituted or unsubstituted pyrrolyl, furanyl, oxazolyl, isoxazolyl, thienyl, thiazolyl, isothiazolyl, thiadiazolyl, oxadiazolyl, imidazolyl, pyrazolyl, triazolyl, pyridazinyl, pyrazinyl, pyridyl, pyrimidinyl, triazinyl, indolyl, quinolyl, isoquinolyl, acridinyl, purinyl, pteridinyl, benzofuranyl, benzothienyl, benzoimidazolyl, benzothiazolyl, benzotriazolyl, benzoxadiazolyl, benzoxazolyl, cinnoline, quinoxalinyl, dibenzofuranyl, dibenzothienyl, carbazolyl, phenanthrolinyl, indolizinyl, naphthridinyl, and phthalazinyl.

[0022] In the present application, "substituted" means that one or more hydrogens in the above group are each independently replaced with deuterium, tritium, F, Cl, Br, I, NO2, C1-C12 alkyl, C2-C12 alkenyl, phenyl, naphthyl, and C2-C10 heteroaryl.

[0023] Preferably, in the present application, "substituted" means that one or more hydrogens in the above group are each independently replaced with deuterium, tritium, F, Cl, Br, I, NO2, C1-C12 alkyl, C2-C12 alkenyl, phenyl, naphthyl, and C2-C10 heteroaryl.

[0024] Preferably, the molecular structure general formula is represented by one of the following chemical formulae I-2 to I-17:

[0025]

[0026]

[0027] In some embodiments, as an example, the compound is selected from any one of the following, but the present application is not limited thereto,

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034] Preparation method

[0035] The application also provides a preparation method of the electron transport layer compound, specifically, each component of the compound is prepared by coupling through Suzuki reaction.

[0036] Preferably, the preparation method comprises the following steps:

[0037]

[0038] The above scheme is directed to intermediate C which is prior art and can be directly purchased or used. In particular, when intermediate E is also prior art and can be directly purchased or used, it can be directly reacted with raw material F. When intermediate C is not prior art, the preparation method further comprises the following preparation process of intermediate C:

[0039]

[0040] In the flow chart, one of group A and group B is a boronic acid group (B(OH)2) or a boronic ester group, and the other is a halogen group, preferably I, Br, or Cl. Group A and group B are coupled through Suzuki reaction.

[0041] Display panel

[0042] The application also provides a display panel comprising an organic electroluminescent device, the organic electroluminescent device comprising an anode, a cathode, and a multi-layer organic film layer between the anode and the cathode, the multi-layer organic film layer comprising at least an emission layer (EML) and an electron transport layer (ETL), wherein the electron transport layer comprises one or more of the compounds according to the application.

[0043] The emission layer can comprise an emission material known in the art. Further, the emission material can comprise a host material and a dopant material. The host material can be selected from host emission materials known in the art and / or one or more of the compounds according to the application. The dopant material can be selected from fluorescent emission materials, phosphorescent emission materials, or thermally activated delayed fluorescence (TADF) emission materials, etc. according to different emission principles; and can be selected from blue emission materials, green emission materials, red emission materials, etc. according to different emission colors. The host material known in the art can be selected according to different emission principles and emission colors of the guest material; and can be a fluorescent host material, a unipolar host material, a bipolar host material, a double host material, etc. and can be a blue host material, a green host material, a red host material.

[0044] In the display panel of the present application, the multilayer organic film layer can also contain other functional layers. As an example, the other functional layers can include a hole blocking layer (HBL). For example, the hole blocking layer is laminated between the light emitting layer and the electron transport layer. In some embodiments, the hole blocking material (HBM) of the hole blocking layer (HBL) can be selected from the HBM known in the art (such as BCP, TPBi, TmPyPB, DPEPO, TAZ, etc.) and / or any one or several of the compounds described in the present application.

[0045] In some embodiments, the other functional layers can also include a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a prime layer, an electron injection layer (EIL), etc. The materials of each layer (such as the hole injection material HIM, the hole transport material HTM, the electron blocking material EBM, the electron injection material EIM) can be selected from the corresponding materials known in the art, respectively.

[0046] Display device

[0047] The present application provides a display device comprising the display panel described in the present application. Examples of the display device include but are not limited to mobile phones, computers, televisions, smart watches, smart cars, VR or AR headsets, etc., and the present application does not make special limitations on this.

[0048] Advantages

[0049] Through the above technical solutions, compared with the prior art, the present application has the following advantages:

[0050] The nitrogen atom-containing heterocyclic electron transport layer compound provided by the present application has the performance advantages of low driving voltage, high efficiency and long service life when used to prepare an organic electroluminescent device.

[0051] 1. The compound of the present application simultaneously introduces two or more functional groups with electron transport performance in a single molecule: triazine (or pyrimidine or pyridine), and cyano pyridine or cyano pyrimidine or cyano pyridazine or cyano pyrazine or cyano triazine, which improves the electron transport performance and improves the problem of electron-hole imbalance in the organic electroluminescent device, thereby improving the light emitting efficiency;

[0052] 2. Due to the introduction of the strong electron-withdrawing group cyano, the HOMO / LUMO values of the compound of the present application are adjusted, so that the energy levels in the device are more matched with the light emitting layer and the electron injection layer, thereby increasing the efficiency;

[0053] 3, The present application introduces a bridging conjugated group at the adjacent aromatic ring of triazine (or pyrimidine or pyridine), and the adjacent substitution increases the spatial distortion of the single molecule of the compound, so that the crystallinity of the electron transport layer prepared from the compound is reduced, the molecular aggregation is reduced, the carrier transport trap is not easy to form, thereby reducing the driving voltage of the OLED device, improving the luminous efficiency and the service life. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0055] Figure 1 The drawing is the nuclear magnetic resonance hydrogen spectrum of the synthesis example 1 of the present application. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present application, not all 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 scope of protection of the present application.

[0057] Synthesis example 1 (compound 1)

[0058]

[0059] The raw material / intermediate C-1 (CAS No. 2647381-07-3, 100 mmol), raw material D-1: 4,4'-dibromobiphenyl (100 mmol) were added to a mixed solvent of toluene / ethanol / water, and a catalyst Pd(PPh)3 / potassium carbonate / tetrabutylammonium chloride was added, and the reaction was carried out under reflux for 20 hours under nitrogen protection. After the reaction was completed, it was cooled to room temperature, filtered with diatomite to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, the organic phase was retained, and then the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, anhydrous magnesium sulfate was used for drying, and a rotary evaporator was used to remove the solvent. The remaining material was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=4:1) to obtain intermediate E-1 (73.07 mmol).

[0060] Intermediate E-1 (73.07 mmol), starting material F-1 (CAS No. 2756733-15-8, 73.07 mmol) were added to a mixture of toluene / ethanol / water, potassium carbonate and catalyst Pd(PPh)3 were added, and the reaction was carried out under reflux for 20 hours under nitrogen. After the reaction was completed, it was allowed to cool to room temperature, filtered using celite, and the salt and catalyst were removed. After the filtrate was cooled to room temperature, it was washed with water three times, the organic phase was retained, and then the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, they were dried using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 4:1) to obtain compound 1 (52.85 mmol).

[0061] The resulting compound 1 was analyzed, and the results were as follows:

[0062] HPLC purity: >99.3%.

[0063] Mass spectrometry test: Theoretical value was 689.82; test value was 690.04.

[0064] Elemental analysis:

[0065] Theoretical value was C, 85.32; H, 4.53; N, 10.15.

[0066] Test value was C, 85.48; H, 4.61; N, 10.28.

[0067] Synthesis Example 2 (compound 5)

[0068]

[0069] Starting material / intermediate C-5 (CAS No. 2647381-07-3, 100 mmol), starting material D-5: p-bromobenzoic acid (CAS No. 5467-74-3, 100 mmol) were added to a mixture of toluene / ethanol / water, catalyst Pd(PPh)3 / potassium carbonate / tetrabutylammonium chloride were added, and the reaction was carried out under reflux for 20 hours under nitrogen. After the reaction was completed, it was allowed to cool to room temperature, filtered using celite, and the salt and catalyst were removed. After the filtrate was cooled to room temperature, it was washed with water three times, the organic phase was retained, and then the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, they were dried using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 4:1) to obtain intermediate E-5 (76.02 mmol).

[0070] Intermediate E-5 (76.02 mmol), starting material F-5 (CAS No. 2756733-15-8, 73.07 mmol) were added to a mixture solvent of toluene / ethanol / water, and potassium carbonate and catalyst Pd(PPh)3 were added, and the reaction was carried out under reflux for 20 hours under nitrogen protection. After the reaction was completed, it was cooled to room temperature, filtered using diatomite, and the salt and catalyst were removed. After the filtrate was cooled to room temperature, it was washed with water three times, and the organic phase was retained, and then the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, anhydrous magnesium sulfate was used for drying, and a rotary evaporator was used to remove the solvent. The remaining material was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 4:1) to obtain compound 5 (57.56 mmol).

[0071] The obtained compound 5 was subjected to detection analysis, and the results were as follows:

[0072] HPLC purity: >99.5%.

[0073] Mass spectrometry test: the theoretical value was 613.72; the test value was 614.17.

[0074] Elemental analysis:

[0075] Theoretical value: C, 84.15; H, 4.43; N, 11.41.

[0076] Test value: C, 84.34; H, 4.51; N, 11.72.

[0077] Synthesis Example 3 (compound 8)

[0078]

[0079] Starting material / intermediate C-8 (CAS No. 2492545-28-3, 100 mmol), starting material D-8: p-dibromobenzene (CAS No. 106-37-6, 100 mmol) were added to a mixture solvent of toluene / ethanol / water, and catalyst Pd(PPh)3 / potassium carbonate / tetrabutylammonium chloride were added, and the reaction was carried out under reflux for 20 hours under nitrogen protection. After the reaction was completed, it was cooled to room temperature, filtered using diatomite, and the salt and catalyst were removed. After the filtrate was cooled to room temperature, it was washed with water three times, and the organic phase was retained, and then the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, anhydrous magnesium sulfate was used for drying, and a rotary evaporator was used to remove the solvent. The remaining material was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 4:1) to obtain intermediate E-2 (71.94 mmol).

[0080] Intermediate E-8 (71.94 mmol), starting material F-8 (CAS No. 2756733-15-8, 71.94 mmol) were added to a mixture solvent of toluene / ethanol / water, and potassium carbonate and catalyst Pd(PPh)3 were added, and the reaction was carried out under reflux for 20 hours under nitrogen protection. After the reaction was completed, it was cooled to room temperature, and diatomite was used for filtration to remove the salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, and the organic phase was retained, and then the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, anhydrous magnesium sulfate was used for drying, and a rotary evaporator was used to remove the solvent. The remaining material was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 4:1) to obtain compound 8 (54.53 mmol).

[0081] The obtained compound 8 was subjected to detection analysis, and the results were as follows:

[0082] HPLC purity: >99.7%.

[0083] Mass spectrometry test: the theoretical value was 613.72; the test value was 614.22.

[0084] Elemental analysis:

[0085] The theoretical value was: C, 84.15; H, 4.43; N, 11.41.

[0086] The test value was: C, 84.26; H, 4.54; N, 11.58.

[0087] Synthesis Example 4 (compound 61)

[0088]

[0089] Starting material / intermediate C-61 (CAS No. 2492545-28-3, 100 mmol), starting material D-61: p-dibromobenzene (CAS No. 106-37-6, 100 mmol) were added to a mixture solvent of toluene / ethanol / water, and catalyst Pd(PPh)3 / potassium carbonate / tetrabutylammonium chloride were added, and the reaction was carried out under reflux for 20 hours under nitrogen protection. After the reaction was completed, it was cooled to room temperature, and diatomite was used for filtration to remove the salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, and the organic phase was retained, and then the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, anhydrous magnesium sulfate was used for drying, and a rotary evaporator was used to remove the solvent. The remaining material was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 4:1) to obtain intermediate E-61 (72.51 mmol).

[0090] Intermediate E-61 (72.51 mmol), starting material F-61 (CAS No. 2756733-15-8, 72.51 mmol) were added to a mixture solvent of toluene / ethanol / water, potassium carbonate and catalyst Pd(PPh)3 were added, and the reaction was carried out under reflux for 20 hours under nitrogen protection. After the reaction was completed, it was cooled to room temperature, filtered using diatomite to remove the salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, the organic phase was retained, and then the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, anhydrous magnesium sulfate was used for drying, and a rotary evaporator was used to remove the solvent. The remaining material was purified by column chromatography using a mixture solution of dichloromethane and petroleum ether (V:V = 4:1) to obtain compound 61 (53.67 mmol).

[0091] The obtained compound 61 was subjected to detection analysis, and the results were as follows:

[0092] HPLC purity: >99.7%.

[0093] Mass spectrometry test: the theoretical value was 663.78; the test value was 614.22.

[0094] Elemental analysis:

[0095] The theoretical value was: C, 85.05; H, 4.40; N, 10.55.

[0096] The test value was: C, 84.56; H, 4.55; N, 11.31.

[0097] The synthesis methods of other compounds were the same as the above examples, and will not be described one by one. The mass spectrometry and molecular formula of other synthesis examples and the yield are shown in Table 1 below:

[0098] Table 1

[0099]

[0100] Device example (1):

[0101] Manufacture of an organic electroluminescent device containing the example compound

[0102] a, ITO anode: the ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150 nm was cleaned in distilled water for 2 times, ultrasonic washing for 30 min, and then repeatedly cleaned with distilled water for 2 times, ultrasonic washing for 10 min. After washing, it was transferred to an equal spin dryer for spinning, and finally baked in a vacuum oven at 220°C for 2 hours. After baking, it was cooled and used. The substrate was used as an anode, and a deposition machine was used to perform a device process, and other functional layers were sequentially deposited thereon.

[0103] b、HIL (hole injection layer): The hole injection layer material HT-1 and P-dopant were vacuum evaporated at an evaporation rate of 0.1 A / s, with a ratio of 97:3, and a thickness of 10 nm. The chemical formula of the HT-1 and P-dopant is shown below.

[0104] c、HTL (hole transport layer): The HT-1 was vacuum evaporated at an evaporation rate of 0.1 A / s on the hole injection layer as a hole transport layer with a thickness of 130 nm.

[0105] d、light-emitting auxiliary layer: The EBL-1 was vacuum evaporated at an evaporation rate of 0.1 A / s on the hole transport layer as a light-emitting auxiliary layer with a thickness of 10 nm.

[0106] e、EML (emitting layer): Then, the host material (Host) and the dopant material (Dopant) were vacuum evaporated at an evaporation rate of 0.1 A / s on the light-emitting auxiliary layer as an emitting layer with a thickness of 20 nm, and the chemical formula of the Host and the Dopant is shown below. The evaporation rate ratio of the Host and the Dopant is 98:2.

[0107] f、HBL (hole blocking layer): The HB-1 was vacuum evaporated at an evaporation rate of 0.1 A / s on the emitting layer as a hole blocking layer with a thickness of 5 nm.

[0108] g、ETL (electron transport layer): The compound 1 provided in the above embodiment was vacuum evaporated at an evaporation rate of 0.1 A / s on the hole blocking layer as an electron transport layer with a thickness of 30 nm.

[0109] h、EIL (electron injection layer): The Yb film layer was evaporated at an evaporation rate of 0.1 A / s to form an electron injection layer with a thickness of 1.0 nm.

[0110] i、cathode: Magnesium and silver were evaporated at an evaporation rate ratio of 1:9 to obtain the OLED device with a thickness of 18 nm.

[0111] j、light extraction layer: The CPL-1 was vacuum evaporated at an evaporation rate of 0.1 A / s on the cathode as a light extraction layer with a thickness of 70 nm. Subsequently, the substrate after evaporation was encapsulated. First, the cleaned cover plate was coated with UV glue by using a coating device, and then the coated cover plate was moved to the pressing section, the substrate after evaporation was placed on the end of the cover plate, and finally the substrate and the cover plate were bonded under the action of the bonding device, and the UV glue was cured by light.

[0112] The chemical structure of the materials used is shown below:​​​​​​​​​

[0113]

[0114] Device Example (2) - Device Example (20) are prepared according to the above method, by replacing the compound 1 used in Device Example (1) with compound 5, 8, 61, 3, 7, 13, 15, 19, 22, 28, 33, 38, 44, 55, 59, 62, 67, 73, 80, respectively, as the electron transport layer.

[0115] Device Control Example (1) - The device control example provides an organic electroluminescent device, the only difference between the preparation method of the organic electroluminescent device and device example (1) is that the organic electroluminescent device is respectively prepared by replacing the electron transport layer (compound 1) in the above device example (1) with the existing comparative compounds A, B for evaporation, to prepare device control examples (1) - (2). The chemical structural formula of comparative compounds A, B is:

[0116] Comparative compound

[0117]

[0118] The driving voltage, luminous efficiency, BI value and lifetime of the organic electroluminescent devices obtained by the above device examples (1) - (20) and device control examples (1) - (2) are characterized under 1000 (nits) brightness, and the test results are as follows Table 2:

[0119] Table 2

[0120]

[0121]

[0122] From the above table, it can be seen that the organic electroluminescent device prepared by the electron transport layer compound provided by the present application as the electron transport layer has lower starting voltage, luminous efficiency and lifetime, and the efficiency is significantly improved. The present application introduces a bridging conjugated group adjacent to the adjacent aromatic ring of triazine (or pyrimidine or pyridine), and the adjacent substitution increases the spatial twist of the single molecule of the compound, thereby reducing the crystallinity of the electron transport layer prepared from the compound, reducing molecular aggregation, and not easily forming carrier transport traps. Due to the introduction of the strong electron-withdrawing group cyano, the HOMO / LUMO value of the compound of the present application is adjusted, so that it is more matched with the energy level of the light-emitting layer and the electron injection layer in the device, thereby increasing the efficiency; the organic electroluminescent device prepared by the electron transport material of the present application has lower starting voltage, luminous efficiency and lifetime, and the efficiency is significantly improved.

[0123] Many modifications and variations of this application can be apparent to those of ordinary skill in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that the application cover the modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

[0124] Each of the embodiments described in this specification has at least one important aspect, but individually they do not fully describe the application. However, some aspects are described with a certain level of specificity in order to fully convey the specifics of the application to the skilled artisan. A combination of aspects can be employed without

[0125] The preceding description of disclosed embodiments is not intended to be exhaustive or to be unduly restrictive of the present application. Many modifications and variations to the described embodiments will be apparent to those skilled in the art upon reading this description. It is intended that the scope of the application should only be defined by the appended claims, and not by the description.

[0126] The specification and drawings are, accordingly to be regarded in an illustrative rather than a restrictive sense.

Claims

1. An electron transport layer compound, the general molecular formula of which is represented by chemical formula I: In the general formula, Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C2-C30 heteroaryl groups; Z1, Z2, and Z3 are independently selected from C or N, and at least one of them is N; preferably, at least two of them are N; most preferably, Z1, Z2, and Z3 are all N. Ar is selected from substituted or unsubstituted C6-C30 aryl groups or substituted or unsubstituted C5-C30 heteroaryl groups; Ar is fused with the adjacent benzene ring and ring-fused. R1 is a substituent, numbered 0, 1, or 2; each is independently selected from hydrogen, deuterium, tritium, -CN, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C3-C30 heteroaryl groups. L is selected from the linking bond, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C3-C30 heteroaryl groups; Y1 to Y5 are each independently selected from C, N, C-CN or C-Ar3, and at least one is N while the other is C-CN; wherein Ar3 is a substituted or unsubstituted C6 to C30 aryl or a substituted or unsubstituted C3 to C30 heteroaryl.

2. The compound according to claim 1, characterized in that: In Formula 1, Ar together with the adjacent benzene ring has the following structural choice:

3. The compound according to claim 1, characterized in that: Ar3 is selected from:

4. The compound according to claim 1, characterized in that: The term "substituted or unsubstituted C6-C30 aryl" is independently selected from substituted or unsubstituted phenyl, naphthyl, phenanthryl, anthracene, biphenyl, triphenylene, pyrene, spirobisfluorene, perylene, indene, azulene, and benzophenanthryl; The term "substituted or unsubstituted C3-C30 heteroaryl" is independently selected from substituted or unsubstituted pyrrole, furanyl, oxazolyl, isoxazolyl, thiophene, thiazolyl, isothiazolyl, thiadiazolyl, oxadiazolyl, imidazolyl, pyrazolyl, triazole, pyrazinyl, pyridinyl, pyrimidinyl, triazinyl, indolyl, quinolinyl, isoquinolinyl, acridineyl, purinyl, pteridineyl, benzofuranyl, benzothiophene, benzoimidazolyl, benzothiazolyl, benzotriazolyl, benzooxadiazolyl, benzoxazolyl, cinnamoline, quinoxolinyl, dibenzofuranyl, dibenzothiophene, carbazolyl, phenanthrolinel, inazinyl, naphridinyl, and phthalazinyl.

5. The compound according to claim 1, characterized in that: Its molecular structure is represented by one of chemical formulas I-2 to I-17:

6. The compound according to claim 1, characterized in that: The compound is selected from any one of the following:

7. A method for preparing an electron transport layer compound as described in any one of claims 1-6, characterized in that... The specific preparation method involves coupling the constituent groups of the compound via a Suzuki reaction; the preparation method includes the following steps: In this group, one of group A and group B is a boric acid group (B(OH)2) or a borate ester group, and the other is a halogen group, preferably I, Br, or Cl; group A and group B are coupled via a Suzuki reaction.

8. The preparation method according to claim 7, characterized in that: The preparation method further includes the following preparation process for intermediate C:

9. A display panel comprising an organic electroluminescent device, the organic electroluminescent device comprising an anode, a cathode, and a multilayer organic film layer located between the anode and the cathode, the multilayer organic film layer comprising at least a light-emitting layer (EML) and an electron transport layer (ETL), characterized in that: The electron transport layer comprises one or more compounds as described in any one of claims 1 to 6.

10. A display device comprising the display panel as claimed in claim 9.

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