An organic cover layer material, a method for preparing the same, and an organic electroluminescent device

Abstract

The application provides an organic cover layer material, a preparation method thereof and an organic electroluminescent device, the cover layer material has a general structure of a chemical formula I, the organic cover layer material of the application takes a rigid adamantyl linking amide group as a mother nucleus, can effectively improve the stability and durability after film formation, introduces -F and -CN with electron-withdrawing properties, can inhibit the effect of an external electric field on electrons, thereby reducing the electron polarizability, is matched with a high refractive index CPL, uses the light interference effect to improve the light extraction efficiency, reduces the light loss, and thereby improves the luminous efficiency of the device.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic electroluminescent materials, and relates to an organic capping layer material, a preparation method thereof and an organic electroluminescent device. BACKGROUND

[0002] An organic electroluminescent (OLED) device has a sandwich structure including electrode material film layers and organic functional material layers sandwiched between the electrode film layers. The OELD has made great progress through decades of development. Although the internal quantum efficiency has reached nearly 100%, the external quantum efficiency is only about 20%. Most of the light is confined in the light-emitting device due to factors such as substrate mode loss, surface plasmon loss and waveguide effect, resulting in a large amount of energy loss.

[0003] In a top-emitting device, a layer of organic capping layer (CPL) is evaporated on a transparent (or semi-transparent) electrode to adjust the optical interference distance, suppress the reflection of external light, and suppress the extinction caused by the movement of surface plasmon, thereby improving the light extraction efficiency and enhancing the luminous efficiency of the device.

[0004] Currently, a layer of high-refractive CPL is often added above the cathode to increase the light extraction efficiency. However, a single layer of high-refractive CPL has limited improvement on the performance of the device, and the development of high-refractive materials also has bottlenecks, making it difficult to improve the light extraction efficiency. In the prior art, a high-low refractive stack film structure is formed by CPL layers with different refractive indexes, so that the light emitted from the device forms a microcavity through the high-low refractive film layers, and the light of a specific wavelength is emitted, the emission spectrum is narrowed, the luminous intensity of the light of a specific wavelength is enhanced, and the luminous efficiency of the device is improved. Therefore, it is of great practical application value to develop a low-refractive CPL to improve the luminous efficiency of the device in combination with a high-refractive CPL, while ensuring excellent overall performance such as device lifetime and driving voltage. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application aims to provide an organic capping layer material, a preparation method thereof and an organic electroluminescent device. The organic capping layer material of the present application takes a rigid adamantyl group connected amide group as a mother nucleus, can effectively improve the stability and durability after film formation, introduces -F and -CN with electron-withdrawing properties, can inhibit the effect of electrons under the action of an external electric field, thereby reducing the electronic polarizability, and in combination with a high-refractive CPL, the light extraction efficiency is improved by using the light interference effect, the light loss is reduced, and the luminous efficiency of the device is improved.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] In one aspect, the present application provides an organic capping layer material, the capping layer material having a general structure of Formula I:

[0008]

[0009] In Formula I:

[0010] Ar1is independently selected from the group consisting of substituted phenyl, substituted naphthyl, substituted biphenyl, substituted or unsubstituted adamantyl, wherein the substituents are one or a combination of at least two of -F, -CF3, -CN;

[0011] m is an integer from 1 to 5;

[0012] R1is independently selected from the group consisting of hydrogen, substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, wherein the substituents are one or a combination of at least two of -F, -CF3, -CN;

[0013] L is independently selected from the group consisting of

[0014] R2is independently selected from the group consisting of -F, -CF3, substituted phenyl, substituted naphthyl, substituted or unsubstituted adamantyl, wherein the substituents are one or a combination of at least two of -F, -CF3;

[0015] R3, R4are independently selected from the group consisting of -F, -CF3, substituted phenyl, substituted naphthyl, substituted or unsubstituted adamantyl, wherein the substituents are one or a combination of at least two of -F, -CF3;

[0016] n is independently selected from an integer from 1 to 4 (e.g., 1, 2, 3, or 4);

[0017] p, q are independently selected from an integer from 0 to 4 (e.g., 0, 1, 2, 3, or 4), and p, q cannot be 0 at the same time;

[0018] At least one of Ar1, R2, R3, and R4above is selected from a group containing a fluorine atom;

[0019] wherein * in the above formula indicates a connection point.

[0020] Further preferably, Ar1is independently selected from the following structures:

[0021]

[0022] wherein * in the above formula indicates a connection point.

[0023] Further, more preferred Formula I is as follows:

[0024]

[0025] Further, the organic capping layer material is selected from any one of the compounds represented by the following structural formula:

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036] The capping layer material of the present application can be prepared by synthetic methods known to those skilled in the art. Alternatively, the following preparation method is preferred to prepare:

[0037] (1) reacting starting material A and starting material B to obtain intermediate 1, the reaction formula is as follows:

[0038]

[0039] (2) reacting intermediate 1 and starting material C to obtain intermediate 2, the reaction formula is as follows:

[0040]

[0041] (3) reacting intermediate 2 and starting material D to obtain the organic capping layer material represented by chemical formula I, the reaction formula is as follows:

[0042]

[0043] wherein L, Ar1, m, R1are defined as in chemical formula I of claim 1, Hal1, Hal2are independently selected from chlorine, bromine or iodine; R is independently selected from wherein * is the linking site.

[0044] Preferably, the molar ratio of starting material A and starting material B in step (1) is 1:1-1.3, for example 1:1, 1:1.1, 1:1.2 or 1:1.3.

[0045] Preferably, the reaction of step (1) is carried out in the presence of a base selected from sodium tert-butoxide or potassium tert-butoxide.

[0046] Preferably, the molar ratio of the base to starting material A is 2-4:1, for example 2:1, 2.3:1, 2.5:1, 2.8:1, 3:1, 3.3:1, 3.5:1, 3.8:1 or 4:1.

[0047] Preferably, the reaction of step (1) is carried out in the presence of a palladium catalyst selected from bis(tri-tert-butylphosphine)palladium.

[0048] Preferably, the molar ratio of the palladium catalyst to starting material A is 0.01-0.03:1, for example 0.01:1, 0.02:1 or 0.03:1.

[0049] Preferably, the reaction of step (1) is carried out in the presence of a phosphine ligand selected from any one or a combination of at least two of 2-di-tert-butylphosphino-2',4',6'-triisopropylbiphenyl, tri-tert-butylphosphine, 2-cyclohexyl-2,4,6-triisopropylbiphenyl, triethylphosphine, trimethylphosphine, triphenylphosphine, potassium diphenylphosphinate or di-tert-butylchlorophosphine.

[0050] Preferably, the molar ratio of the phosphine ligand to starting material A is 0.02-0.15:1, for example 0.02:1, 0.03:1, 0.05:1, 0.07:1, 0.09:1, 0.10:1, 0.12:1, 0.14:1 or 0.15:1.

[0051] Preferably, the solvent for the reaction of step (1) is toluene.

[0052] Preferably, the temperature for the reaction of step (1) is 100-120°C, for example 100°C, 105°C, 110°C, 115°C or 120°C, and the reaction time is 1-12 hours, for example 1 hour, 3 hours, 5 hours, 8 hours, 10 hours or 12 hours.

[0053] Preferably, the molar ratio of intermediate 1 to starting material C for step (2) is 1:1-1.2, for example 1:1, 1:1.1 or 1:1.2.

[0054] Preferably, the reaction of step (2) is carried out in the presence of a base selected from triethylamine.

[0055] Preferably, the molar ratio of the base to intermediate 1 is 2-3:1, for example 2:1, 2.3:1, 2.5:1, 2.8:1 or 3:1.

[0056] Preferably, the solvent of the reaction of step (2) is dichloromethane.

[0057] Preferably, the temperature of the reaction of step (2) is 0-35 °C, for example 0 °C, 5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C or 35 °C, and the reaction time is 8-18 hours, for example 8 hours, 9 hours, 10 hours, 12 hours, 14 hours, 16 hours or 18 hours.

[0058] Preferably, the molar ratio of intermediate 2 to starting material D of step (3) is 1 : 1-1.2, for example 1 : 1, 1 : 1.1 or 1 : 1.2.

[0059] Preferably, the reaction of step (3) is carried out in N,N-dimethylformamide in the presence of a basic substance, anhydrous potassium phosphate, and a catalyst, palladium tetrakis(triphenylphosphine), or in toluene, ethanol or water in the presence of a basic substance, potassium carbonate, and a catalyst, palladium acetate and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene.

[0060] Preferably, the molar ratio of the anhydrous potassium phosphate to intermediate 2 is 2-4: 1, for example 2: 1, 2.3: 1, 2.5: 1, 2.8: 1, 3: 1, 3.3: 1, 3.5: 1, 3.8: 1 or 4: 1.

[0061] Preferably, the molar ratio of the palladium tetrakis(triphenylphosphine) to intermediate 2 is 0.01-0.03: 1; for example 0.01: 1, 0.02: 1 or 0.03: 1.

[0062] Preferably, the molar ratio of the potassium carbonate to intermediate 2 is 2-4: 1, for example 2: 1, 2.3: 1, 2.5: 1, 2.8: 1, 3: 1, 3.3: 1, 3.5: 1, 3.8: 1 or 4: 1.

[0063] Preferably, the molar ratio of the palladium acetate to intermediate 2 is 0.01-0.05: 1; for example 0.01: 1, 0.02: 1, 0.03: 1, 0.04: 1 or 0.05: 1.

[0064] Preferably, the molar ratio of the 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene to intermediate 2 is 0.1-0.3: 1, for example 0.1: 1, 0.2: 1 or 0.3: 1.

[0065] Preferably, the temperature of the reaction of step (3) is 70-100 °C, for example 70 °C, 73 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C or 100 °C, and the reaction time is 6-12 h, for example 6 h, 8 h, 10 h or 12 h.

[0066] In a preferred embodiment, the organic capping layer material is prepared according to the following procedure:

[0067]

[0068] in which L, Ar1, m, R1are as defined above in formula I, Hal1, Hal2are independently selected from chlorine, bromine or iodine; R is independently selected from wherein * is the point of attachment.

[0069] In particular, for complex starting materials not disclosed in the literature, classical Schotten-Baumann reactions, Buchwald-Hartwig coupling reactions, Suzuki coupling reactions are synthesized and applied to the present application.

[0070] Specific preparation procedure:

[0071] Step 1 specifically includes the following process:

[0072] The starting material A (1.0 eq), starting material B (1.0-1.3 eq) and sodium tert-butoxide (2.0-4.0 eq) are dissolved in toluene under nitrogen protection, and then bis(triphenylphosphine)palladium (0.01-0.03 eq) and 2-di-tert-butylphosphino-2',4',6'-triisopropylbiphenyl (0.02-0.15 eq) are added, stirred uniformly, and heated to 100-120°C, and refluxed for 1-12 hours; the reaction is detected by thin layer chromatography, after the reaction is completed, the temperature is slightly lowered, and diatomite is used for filtration to remove the salt and catalyst, and the filtrate is cooled to room temperature, and washed with water three times, and the organic phase is reserved, and then the aqueous phase is extracted with dichloromethane; the organic phases are combined, and the solvent is removed by using a rotary evaporator; the intermediate 1 is purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4-1:12).

[0073] Step 2 specifically includes the following process:

[0074] Under ice bath, intermediate 1 (1.0 eq), triethylamine (2.0 eq) and DCM are sequentially added into a reaction container, stirred at 0°C for 10-30 min, and then starting material C (1.0 eq) is slowly added, the obtained mixture is stirred at 0°C for 1-2 h, and then stirred at room temperature for 8-16 h, filtered, the filter cake is dried, and then purified by column chromatography (eluent: a mixed solution of dichloromethane and petroleum ether V:V=1:4-1:16 or petroleum ether), the eluent is concentrated by using a rotary evaporator, dried, and the intermediate 2 is obtained.

[0075] Step 3 specifically includes the following process:

[0076] Under nitrogen protection, the intermediate 2, the raw material D, (dimethylformamide, anhydrous potassium phosphate (2.0-4.0 eq) and tetrakis(triphenylphosphine)palladium (0.01-0.03 eq) or toluene, ethanol, water, potassium carbonate (2.0-4.0 eq), palladium acetate (0.01-0.05 eq) and Xantphos (0.1-0.3 eq) are sequentially added into a reaction vessel, heated to 70-100℃, and reacted for 6-12 h. The obtained product is filtered to remove the salt and catalyst while hot, cooled to room temperature, and extracted with an equal amount of DCM and water. The organic phase is separated and dried by rotary evaporation. The product is purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:4-1:16) to obtain the chemical formula I.

[0077] In another aspect, the present application provides an organic cover layer, wherein the material of the organic cover layer comprises the organic cover layer material as described above.

[0078] In another aspect, the present application provides an organic electroluminescent device, comprising an anode, a cathode, an organic thin film layer disposed between the anode and the cathode, and an organic cover layer disposed on the cathode, wherein the organic cover layer comprises the organic cover layer material as described above.

[0079] Preferably, the organic cover layer comprises a low refractive index cover layer and a high refractive index cover layer, wherein the low refractive index cover layer comprises the organic cover layer material as described above, and the high refractive index cover layer comprises a material with a refractive index of 2.0-2.5 (e.g. 2.0, 2.1, 2.2, 2.3, 2.4 or 2.5).

[0080] Compared with the prior art, the present application has the following advantages:

[0081] The compound of the present application effectively presents the characteristics of a low refractive index cover layer material, and is used in combination with a high refractive index CPL to obtain a device with high luminous efficiency. The compound of the present application takes a rigid adamantyl group connected to an amide group as a mother nucleus, which can effectively improve the stability and durability of the film after forming, and avoids the problem of shortening the service life of the device due to impurities generated in the evaporation of unstable materials. Further introduction of multiple steric groups and electron-withdrawing groups (-F, -CN and other elements with strong electronegativity) can regulate the packing density and electron density of the molecule to adjust the polarizability of the molecule. As a low refractive index CPL, it is combined with a high refractive index CPL, so that the light emitted from the device produces a microcavity through the high-low refractive index film layer, and the light interference effect is used to improve the light extraction efficiency and reduce light loss, thereby improving the luminous efficiency of the device, while having a lower driving voltage and a long service life. BRIEF DESCRIPTION OF DRAWINGS

[0082] Figure 1is the nuclear magnetic resonance hydrogen spectrum of compound 25 provided in embodiment 4 of the present application. DETAILED DESCRIPTION

[0083] The technical solutions of the present application are further illustrated by the specific embodiments below. Those skilled in the art should understand that the embodiments are only to help understand the present application and should not be regarded as specific limitations of the present application.

[0084] In addition, it should be noted that the numerical values given in the following examples are as accurate as possible, but those skilled in the art understand that due to unavoidable measurement errors and experimental operation problems, each number should be understood as an approximate number, not an absolutely accurate number.

[0085] A-1, A-5, A-23, A-25 are the same substance and are prior art, CAS No.: 78598-42-2.

[0086] In the examples, R2, R3, R4 and Ar1 are the same structure, so only one step of Suzuki coupling reaction synthesis can synthesize the target compound.

[0087] Example 1

[0088]

[0089] Under ice bath, raw material A-1 (1.0 eq, CAS No.: 78598-42-2), triethylamine (2.0 eq) and DCM were sequentially added into a reaction vessel, stirred at 0°C for 15 min, then raw material B-1 (1.0 eq, CAS No.: 23950-59-6) was slowly added, the resulting mixture was stirred at 0°C for 1 h, then stirred at room temperature for 12 h, filtered, the filter cake was dried, then purified by column chromatography (eluent: petroleum ether), the eluent was concentrated by rotary evaporator, dried to obtain intermediate 1 (yield: 78.5%).

[0090] Under nitrogen protection, intermediate 1 (1.0 eq), raw material C-1 (1.1 eq, CAS No.: 69807-91-6), dimethylformamide, anhydrous potassium phosphate (3.0 eq) and tetrakis(triphenylphosphine)palladium (0.03 eq) were sequentially added into a reaction vessel, heated to 80°C, reacted for 8 h, the resulting salt and catalyst were filtered out while hot, cooled to room temperature, added equal amount of DCM and water, extracted, separated, the organic phase was rotary evaporated, purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V=1:8) to obtain compound 1 (yield: 90.4%).

[0091] The obtained compound 1 was detected and analyzed, and the results were as follows:

[0092] HPLC purity: >99.8%.

[0093] Mass spectrometry: Waters XEVO TQD, ESI source.

[0094] Test value (ESI, m / Z): [M+H]+): 679.43.

[0095] Elemental analysis:

[0096] Calculated: C, 58.33; H, 3.71; F, 33.55; N, 2.06; O, 2.35;

[0097] Test value: C, 57.96; H, 3.84; F, 33.67; N, 2.46; O, 2.46.

[0098] Example 2

[0099]

[0100] Under ice-bath, raw material A-5 (1.0 eq, CAS No.: 78598-42-2), triethylamine (2.0 eq) and DCM were added into a reaction vessel successively, stirred at 0°C for 15 min, then raw material B-5 (1.0 eq, CAS No.: 23950-59-6) was added slowly, the resulting mixture was stirred at 0°C for 1 h, then stirred at room temperature for 12 h, filtered, the filter cake was dried, then purified by column chromatography (eluent: petroleum ether), the eluent was concentrated by rotary evaporator, dried to obtain intermediate 1 (yield: 78.5%).

[0101] Under nitrogen protection, intermediate 1 (1.0 eq), raw material C-5 (1.1 eq, CAS No.: 325143-04-2), dimethylformamide, anhydrous potassium phosphate (3.0 eq) and tetrakis(triphenylphosphine)palladium (0.03 eq) were added into a reaction vessel successively, heated to 80°C, reacted for 9 h, the resulting mixture was filtered to remove salt and catalyst while hot, cooled to room temperature, added equal amount of DCM and water, extracted, separated, the organic phase was dried by rotary evaporator, purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:9) to obtain compound 5 (yield: 88.9%).

[0102] The resulting compound 5 was detected and analyzed, and the results were as follows:

[0103] HPLC purity: >99.8%.

[0104] Mass spectrometry: Waters XEVO TQD, ESI source.

[0105] Test value ((ESI, m / Z): [M+H]+): 515.43.

[0106] Elemental analysis:

[0107] Calculated value: C, 67.57; H, 4.50; F, 22.11; N, 2.72; O, 3.10;

[0108] Test value: C, 67.21; H, 4.65; F, 22.24; N, 2.83; O, 3.21.

[0109] Example 3

[0110]

[0111] Under ice-bath, raw material A-23 (1.0 eq, CAS No.: 78598-42-2), triethylamine (2.0 eq) and DCM were added into a reaction vessel in turn, stirred at 0℃ for 15 min, then raw material B-23 (1.0 eq, CAS No.: 22019-75-6) was slowly added, the resulting mixture was stirred at 0℃ for 1 h, then stirred at room temperature for 12 h, filtered, the filter cake was dried, then purified by column chromatography (eluent: petroleum ether), the eluent was concentrated by rotary evaporator, dried to obtain intermediate 1 (yield: 76.3%).

[0112] Under nitrogen protection, intermediate 1 (1.0 eq), raw material C-23 (1.1 eq, CAS No.: 325143-04-2), dimethylformamide, anhydrous potassium phosphate (3.0 eq) and tetrakis(triphenylphosphine)palladium (0.03 eq) were added into a reaction vessel in turn, heated to 80℃, reacted for 12 h, the resulting mixture was filtered to remove salt and catalyst while hot, cooled to room temperature, added equal amount of DCM and water, extracted, separated, the organic phase was rotary evaporated to dryness, then purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:10) to obtain compound 23 (yield: 84.1%).

[0113] The obtained compound 23 was subjected to detection analysis, and the results were as follows:

[0114] HPLC purity: >99.7%.

[0115] Mass spectrometry test: Waters XEVO TQD mass spectrometer, ESI source.

[0116] Test value ((ESI, m / Z): [M+H]+): 645.43.

[0117] Elemental analysis:

[0118] Calculated: C, 55.23; H, 3.05; F, 38.35; N, 1.57; O, 1.79;

[0119] Test: C, 64.73; H, 3.89; F, 26.60; N, 2.29; O, 2.61.

[0120] Example 4

[0121]

[0122] Under ice-bath, raw material A-25 (1.0 eq, CAS No.: 78598-42-2), triethylamine (2.0 eq) and DCM were added into a reaction vessel successively, stirred at 0°C for 15 min, then raw material B-25 (1.0 eq, CAS No.: 22019-75-6) was added slowly, the resulting mixture was stirred at 0°C for 1 h, then stirred at room temperature for 12 h, filtered, the filter cake was dried, then purified by column chromatography (eluent: petroleum ether), the eluent was concentrated by rotary evaporator, dried to obtain intermediate 1 (yield: 76.3%).

[0123] Under nitrogen protection, intermediate 1 (1.0 eq), raw material C-25 (1.1 eq, CAS No.: 69807-91-6), dimethylformamide, anhydrous potassium phosphate (3.0 eq) and tetrakis(triphenylphosphine)palladium (0.03 eq) were added into a reaction vessel successively, heated to 80°C, reacted for 10 h, the resulting mixture was filtered to remove salt and catalyst while hot, cooled to room temperature, added equal amount of DCM and water, extracted, separated, the organic phase was dried by rotary evaporator, purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:10) to obtain compound 25 (yield: 85.5%).

[0124] The resulting compound 25 was detected and analyzed, and the results were as follows:

[0125] HPLC purity: >99.7%.

[0126] Mass spectrometry test: Waters XEVO TQD mass spectrometer, ESI source.

[0127] Test value ((ESI, m / Z): [M+H]+): 891.44.

[0128] Elemental analysis:

[0129] Calculated: C, 55.23; H, 3.05; F, 38.35; N, 1.57; O, 1.79;

[0130] Test values are: C, 54.85; H, 3.17; F, 38.46; N, 1.69; O, 1.93.

[0131] The nuclear magnetic resonance hydrogen spectrum is shown in Figure 1

[0132] Examples 5-45

[0133] The synthesis of the following compounds was completed according to the synthesis method of Examples 1 to 4, and the mass spectrometer used was Waters XEVOTQD, which has low accuracy, and the ESI source was used for testing, and the mass spectrometry test values are shown in Table 1 below.

[0134] Table 1 Mass spectrometry test values of Examples 5-45

[0135]

[0136]

[0137]

[0138] In addition, other compounds of the present application can be obtained according to the synthesis method of the above-mentioned examples, and therefore, they will not be listed one by one here.

[0139] Preparation of single-layer films for optical characteristic evaluation:

[0140] Examples 1 to 45 and comparative compounds a to g were each made into an evaporation film with a film thickness of 80 nm on a silicon substrate, and the refractive index n and extinction coefficient k values at wavelengths of 460 nm, 530 nm and 620 nm were measured, and the measurement data are shown in Table 2 below, and the structures of the comparative compounds a to g are shown below.

[0141]

[0142] Table 2 Test results of the refractive index n and extinction coefficient k values of the compounds prepared in Examples 1-45 and compounds a to g

[0143]

[0144]

[0145]

[0146] ​As shown in Table 2, the compounds prepared in Examples 1-45 have a refractive index of 1.349-1.469 in various color domains, which is lower than the refractive index of the comparative compounds a-g, and the difference in refractive index between 460 nm, 530 nm and 620 nm is less than 0.12, so that the material can emit red, green and blue light uniformly in the light-emitting device, which meets the refractive index requirement of the covering layer of the light-emitting device, and the extinction coefficient k value is almost 0 in various color domains, which does not affect the light emission of the light-emitting layer.

[0147] Device Example 1: Preparation of an organic electroluminescent device

[0148] The prepared OLED device has the structure of: ITO anode / HIL / HTL / Prime / EML / HBL / ETL / EIL / cathode / CPL-1 / CPL-2.

[0149] a, ITO anode: an ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 1.1-1.1-0.05 mm was cleaned twice in distilled water, ultrasonic washing for 30 min, and then cleaned twice in distilled water, ultrasonic washing for 10 min. After washing, methanol, acetone and isopropanol were sequentially ultrasonic washed (5 min each time), dried, and then transferred to a plasma cleaning machine for washing for 5 min, and then sent to an evaporation machine. The substrate was used as an anode, and other functional layers were sequentially evaporated thereon. b, HIL (hole injection layer): a hole injection layer material HT and P-dopant were vacuum evaporated at an evaporation rate of 0.1-0.1 nm / s. The evaporation rate ratio of the HT and P-dopant was 97:3, and the thickness was 10 nm.

[0150] c, HTL (hole transport layer): 120 nm of HT as a hole transport layer was vacuum evaporated on the hole injection layer at an evaporation rate of 0.1-0.1 nm / s.

[0151] d, Prime (light-emitting auxiliary layer): 5 nm of Prime as a light-emitting auxiliary layer was vacuum evaporated on the hole transport layer at an evaporation rate of 0.1-0.1 nm / s. e, EML (light-emitting layer): then, 20 nm of a host material (Host) and a doping material (Dopant) as a light-emitting layer were vacuum evaporated on the above light-emitting auxiliary layer at an evaporation rate of 0.1-0.1 nm / s. The evaporation rate ratio of the Host and the Dopant was 98:2.

[0152] f, HBL (hole blocking layer): 10 nm of a hole blocking layer material (HBL) was vacuum evaporated on the light-emitting layer at an evaporation rate of 0.1-0.1 nm / s.

[0153] g, ETL (electron transport layer): 30 nm of an electron transport layer material (ETL) was vacuum evaporated on the hole blocking layer at an evaporation rate of 0.1-0.1 nm / s. h, EIL (electron injection layer): 1-2 nm of an electron injection layer material (EIL) was vacuum evaporated on the electron transport layer at an evaporation rate of 0.1-0.1 nm / s.

[0154] ​​​The hole blocking layer HB is vacuum deposited at a rate of 5.0 nm in thickness.

[0155] g、ETL (electron transport layer): Liq is vacuum deposited at a rate of 5.0 nm in thickness as the electron transport layer. The ET and Liq are vacuum deposited at a rate of 30 nm in thickness as the electron transport layer, wherein the rate of ET and Liq is 50:50.

[0156] h、EIL (electron injection layer): Yb is vacuum deposited at a rate of 1.0 nm in thickness as the electron injection layer. The Yb is vacuum deposited at a rate of 1.0 nm in thickness as the electron injection layer.

[0157] i、Cathode: Mg and Ag are vacuum deposited at a rate of 13 nm in thickness, wherein the rate of Mg and Ag is 1:9, to obtain the OLED device. The Mg and Ag are vacuum deposited at a rate of 13 nm in thickness, wherein the rate of Mg and Ag is 1:9, to obtain the OLED device.

[0158] j、CPL-1 (low refractive index cover layer): Compound 1 is vacuum deposited at a rate of 20 nm in thickness on the cathode as the low refractive index cover layer. The Compound 1 is vacuum deposited at a rate of 20 nm in thickness on the cathode as the low refractive index cover layer.

[0159] k、CPL-2 (high refractive index cover layer): CPL-A is vacuum deposited at a rate of 50 nm in thickness on the low refractive index CPL obtained in step j as the high refractive index cover layer. The CPL-A is vacuum deposited at a rate of 50 nm in thickness on the low refractive index CPL obtained in step j as the high refractive index cover layer.

[0160] l、Subsequently, the substrate after the deposition is encapsulated. First, the cleaned cover plate is coated with UV glue by using a gluing device, then the coated cover plate is moved to a pressing section, the substrate after the deposition is placed on the end of the cover plate, and finally the substrate and the cover plate are adhered under the action of the adhering device, and the UV glue is cured by light irradiation.

[0161] The structural formula of the HT, P-dopant, Prime, Host, Dopant, HB, ET, and CPL-A used in the device embodiment 1 is shown as follows:

[0162]

[0163] Referring to the method provided in the device embodiment 1, the corresponding compounds in Table 3 are respectively used to replace the compound 1 to perform the deposition of the low refractive index cover layer, and the corresponding organic electroluminescent devices are prepared and are respectively recorded as device embodiments 2-45.

[0164] Referring to the method provided in the device embodiment 1, the comparative compounds a-g are respectively used to replace the low refractive index cover layer (compound 1) in the device embodiment 1 to perform the deposition, and are respectively recorded as device comparative examples 1-7.

[0165] Device Comparative Example 8, 9: Comparative compounds h, i (specific structures are shown below) were simultaneously replaced with compound 1 in CPL-1 and CPL-A in CPL-2 in Device Example 1 above to be evaporated, denoted as device comparative example 8, 9. That is, the CPL-1 and CPL-2 layers in device comparative example 8 and 9 are the same, which are compound h, i, respectively.

[0166] Device Comparative Example 10: CPL-A in CPL-2 was replaced with compound 1 in Device Example 1 above to be evaporated, denoted as device comparative example 10. That is, the CPL-1 and CPL-2 layers in device comparative example 10 are the same, which are CPL-A.

[0167]

[0168] The driving voltage, BI value and lifetime of the organic electroluminescent devices obtained from Device Example 1-45 and Device Comparative Example 1-10 above were characterized under 1000 (nits) brightness, and the test results are shown in Table 3 below:

[0169] Table 3 Device test results

[0170]

[0171]

[0172]

[0173] As known by those skilled in the art, in a blue top-emitting device, the luminous efficiency is greatly affected by the chromaticity, therefore, the factor of the influence of chromaticity on efficiency is considered, and the luminous efficiency and CIEy ratio are defined as BI value, that is, BI = (cd / A) / CIEy.

[0174] The compound of the present application introduces -F, -CN and other electronegative elements on the rigid adamantane amide group, which can inhibit the effect of the external electric field on the electron, thereby reducing the electronic polarizability. As can be seen from Table 3, the device performance of device examples 1-45 prepared by the combination of the compound of the present application and high refractive index CPL is better than that of the device prepared by the combination of low refractive index CPL (compounds a-g) and high refractive index CPL in the prior art, and also better than that of the device prepared by only containing high refractive index CPL (compound h, compound i and CPL-A) in the prior art. Under the same device conditions, the compound in the present application has higher luminous efficiency. After the low refractive index CPL and the high refractive index CPL provided by the present application are used to form a film, microcavities are generated, which interfere with each other, can better play the role of light condensation, further reduce light loss, and effectively improve the light extraction efficiency.

[0175] Applicants declare that the organic cover layer material and the preparation method thereof, the organic electroluminescent device of the present application are illustrated by the above-mentioned embodiments, but the present application is not limited to the above-mentioned embodiments, i.e. it does not mean that the present application must rely on the above-mentioned embodiments to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the raw materials selected by the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. An organic coating material, wherein the general structural formula of the coating material is chemical formula I: ； In chemical formula I: Ar1 is independently selected from substituted phenyl, substituted naphthyl, substituted biphenyl, substituted or unsubstituted adamantyl, wherein the substituent is one or a combination of at least two of -F, -CF3, and -CN; m is an integer from 1 to 5; R1 is independently selected from hydrogen, substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, wherein the substituent is one or a combination of at least two of -F, -CF3, and -CN; L is selected independently or ; R2 is independently selected from -F, -CF3, substituted phenyl, substituted naphthyl, substituted or unsubstituted adamantyl, wherein the substituent is one or a combination of at least two of -F and -CF3; R3 and R4 are independently selected from -F, -CF3, substituted phenyl, substituted naphthyl, substituted or unsubstituted adamantyl, wherein the substituent is one or a combination of at least two of -F and -CF3. n is an integer independently selected from 1 to 4; p and q are independently selected from integers from 0 to 4, and p and q cannot be 0 at the same time; At least one of Ar1, R2, R3 and R4 mentioned above is selected from a group containing a fluorine atom; In the above formula, * represents a connection point.

2. The organic coating material according to claim 1, characterized in that, Ar1 is independently selected from the following structures: ； In the above formula, * represents a connection point.

3. The organic coating material according to claim 1, characterized in that, The organic capping material has the structure described in chemical formula Ia or chemical formula Ib: 。 4. The organic coating material according to any one of claims 1-3, characterized in that, The organic coating material is selected from any one of the compounds shown in the following structural formulas: 。 5. The method for preparing the organic coating material according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: (1) Raw material A and raw material B react to obtain intermediate 1, and the reaction formula is as follows: ； (2) Intermediate 1 reacts with raw material C to obtain intermediate 2, and the reaction formula is as follows: ； (3) Intermediate 2 reacts with raw material D to obtain the organic capping material shown in chemical formula I. The reaction formula is as follows: ； Wherein L, Ar1, m, and R1 are as defined in chemical formula I of claim 1, Hal1 and Hal2 are independently selected from chlorine, bromine, or iodine; R is independently selected from... or , where * represents the connection site.

6. The preparation method according to claim 5, characterized in that, The molar ratio of raw material A and raw material B in step (1) is 1:1-1.

3.

7. The preparation method according to claim 5, characterized in that, The reaction in step (1) is carried out in the presence of an alkaline substance, which is selected from sodium tert-butoxide or potassium tert-butoxide.

8. The preparation method according to claim 7, characterized in that, The molar ratio of the alkaline substance to raw material A is 2-4:

1.

9. The preparation method according to claim 5, characterized in that, The reaction in step (1) is carried out in the presence of a palladium catalyst selected from bis(tritert-butylphosphine)palladium.

10. The preparation method according to claim 9, characterized in that, The molar ratio of the palladium catalyst to raw material A is 0.01-0.03:

1.

11. The preparation method according to claim 5, characterized in that, The reaction in step (1) is carried out in the presence of a phosphine ligand selected from any one or a combination of at least two of 2-di-tert-butylphosphine-2',4',6'-triisopropylbiphenyl, tri-tert-butylphosphine, 2-cyclohexyl-2,4,6-triisopropylbiphenyl, triethylphosphine, trimethylphosphine, triphenylphosphine, potassium diphenylphosphonate, or di-tert-butylphosphine chloride.

12. The preparation method according to claim 11, characterized in that, The molar ratio of the phosphine ligand to raw material A is 0.02-0.15:

1.

13. The preparation method according to claim 5, characterized in that, The solvent for the reaction in step (1) is toluene.

14. The preparation method according to claim 5, characterized in that, The reaction temperature in step (1) is 100-120℃, and the reaction time is 1-12 hours.

15. The preparation method according to claim 5, characterized in that, In step (2), the molar ratio of intermediate 1 to raw material C is 1:1-1.

2.

16. The preparation method according to claim 5, characterized in that, The reaction in step (2) is carried out in the presence of an alkaline substance selected from triethylamine.

17. The preparation method according to claim 5, characterized in that, The molar ratio of the alkaline substance to intermediate 1 is 2-3:

1.

18. The preparation method according to claim 5, characterized in that, The solvent for the reaction in step (2) is dichloromethane.

19. The preparation method according to claim 5, characterized in that, The reaction temperature in step (2) is 0-35℃, and the reaction time is 8-18 hours.

20. The preparation method according to claim 5, characterized in that, In step (3), the molar ratio of intermediate 2 to raw material D is 1:1-1.

2.

21. The preparation method according to claim 5, characterized in that, The reaction described in step (3) is carried out in N,N-dimethylformamide in the presence of anhydrous potassium phosphate and a catalyst tetra(triphenylphosphine)palladium, or in toluene, ethanol or water in the presence of potassium carbonate and a catalyst palladium acetate and 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene.

22. The preparation method according to claim 21, characterized in that, The molar ratio of anhydrous potassium phosphate to intermediate 2 is 2-4:

1.

23. The preparation method according to claim 21, characterized in that, The molar ratio of the tetra(triphenylphosphine)palladium to intermediate 2 is 0.01-0.03:

1.

24. The preparation method according to claim 21, characterized in that, The molar ratio of potassium carbonate to intermediate 2 is 2-4:

1.

25. The preparation method according to claim 21, characterized in that, The molar ratio of palladium acetate to intermediate 2 is 0.01-0.05:

1.

26. The preparation method according to claim 21, characterized in that, The molar ratio of 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene to intermediate 2 is 0.1-0.3:

1.

27. The preparation method according to claim 5, characterized in that, The reaction temperature in step (3) is 70-100℃, and the reaction time is 6-12h.

28. An organic coating layer, characterized in that, The material of the organic coating layer includes the organic coating layer material as described in any one of claims 1-4.

29. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, an organic thin film layer disposed between the anode and the cathode, and an organic capping layer disposed on the cathode, wherein the organic capping layer includes the organic capping layer material as described in any one of claims 1-4.

30. The organic electroluminescent device according to claim 29, characterized in that, The organic coating layer includes a low-refractive-index coating layer and a high-refractive-index coating layer, wherein the low-refractive-index coating layer includes the organic coating layer material as described in any one of claims 1-4, and the high-refractive-index coating layer includes the material with a refractive index of 2.0-2.5.

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