Cyclohexyl-containing electron transport layer compound and organic electroluminescent device thereof

Abstract

The invention belongs to the technical field of organic electroluminescent materials, and particularly relates to a cyclohexyl-containing electron transport layer compound and an organic electroluminescent device thereof, the series of compounds improve the planarity of the structure by introducing substituted cyclohexyl on the premise of maintaining higher electron mobility of the material, so that the organic electroluminescent device has higher electron mobility. The phenomenon that the morphology of a thin film is changed in the using process of the material can be avoided, the film-forming property of the material is improved, the light-emitting efficiency of a device is improved, and the driving voltage is reduced; and meanwhile, it is also guaranteed that the material has enough long gasification state time for use on the display panel production line, and the problem of hole blocking is prevented.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic electroluminescent materials, and particularly relates to an electron transport layer compound containing cyclohexyl and an organic electroluminescent device thereof. Background Art

[0002] OLED (Organic Light Emitting Diode) is a new type of display technology, which has the advantages of self-luminescence, high contrast, wide viewing angle, fast response, etc. The development of OLED technology stems from the improvement and breakthrough of traditional liquid crystal display technology. Its characteristic lies in using an organic thin film as a light-emitting material and emitting light through the current flow under the action of an electric field.

[0003] As OLED products gradually enter the market, people have higher and higher requirements for the performance of such products. The currently used OLED materials and device structures cannot completely solve various problems such as the efficiency, lifespan, and cost of OLED products, and there are problems of low luminous efficiency, high driving voltage, and short service life.

[0004] Therefore, there is an urgent need in this field to study more types of electron transport materials, so that when they are used in OLED devices, the luminous efficiency can be further improved, the driving voltage can be reduced, and the service life can be extended. Summary of the Invention

[0005] To solve the problems in the background art, the first object of the present invention is to provide an electron transport layer compound containing cyclohexyl, and the technical solution is as follows:

[0006] An electron transport layer compound containing cyclohexyl has a structure shown in the following general formula I:

[0007]

[0008] In general formula I, Ar1, Ar2, and Ar3 are each independently selected from substituted or unsubstituted C6-C 36 aryl, substituted or unsubstituted C6-C 36 heteroaryl, or a structure shown in formula I-1 below, and at least one of Ar1, Ar2, and Ar3 has a structure shown in formula I-1 below:

[0009]

[0010] In formula I-1, L is selected from substituted or unsubstituted C6-C 36 aryl, substituted or unsubstituted C6-C 36 heteroaryl, and R is each independently selected from C1-C 18An alkyl group, where n is an integer taken from 1 to 5. When there are substituents, the substituents are selected from pyridyl, cyano, and alkyl groups.

[0011] As a preference of the present invention, Ar1, Ar2, and Ar3 are each independently selected from aryl groups having 6 to 18 carbon atoms or the structure represented by Formula I-1.

[0012] As a preference of the present invention, L is selected from aryl groups having 6 to 24 carbon atoms.

[0013] As a preference of the present invention, R is each independently selected from alkyl groups having 1 to 6 carbon atoms.

[0014] As a preference of the present invention, n is 1 or 2.

[0015] As a preference of the present invention, one of Ar1, Ar2, and Ar3 has the structure represented by Formula I-1.

[0016] As a preference of the present invention, the structure of General Formula I is any one of the following structures:

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033] Another object of the present invention is to provide an organic electroluminescent device, including a first electrode, a second electrode, and an organic material layer disposed therebetween, wherein the organic material layer includes an electron transport layer, and the electron transport layer is prepared from the above-mentioned electron transport layer compound containing cyclohexyl.

[0034] Preferably, the organic electroluminescent device is used to manufacture a display device, a lighting source, a signal lamp, or a sign, and the display device includes a mobile phone display screen, a computer display screen, a television display screen, a smart watch display screen, a smart car display panel, a VR or AR helmet display screen.

[0035] The beneficial effects of the present invention are as follows:

[0036] The electron transport layer compound containing cyclohexyl and the organic electroluminescent device provided by the present invention, wherein, on the premise of maintaining a relatively high electron mobility of the material, by introducing a substituted cyclohexyl group, the planarity of the structure is improved, the phenomenon of film morphology change during the use of the material can be avoided, the film-forming property of the material is improved, and further the luminous efficiency of the device is improved and the driving voltage is reduced; at the same time, it also ensures that the material has a sufficiently long gasification state time on the display panel production line for use, preventing the problem of hole blockage. Detailed implementation manners

[0037] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] For those not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase. Some reaction compounds are purchased from commercial suppliers (Zhengzhou Alpha Chemical Co., Ltd.), and some compounds that cannot be directly purchased are prepared by simple reactions from commercially purchased raw materials. The percentages are all mass percentages, and the temperature is in degrees Celsius (°C). Such method principles, operation processes, conventional post-treatments, passing through silica gel columns, recrystallization purification and other means are well-known to synthetic personnel in the art, and can fully realize the synthesis process to obtain the target product. The reactions in each preparation example are generally carried out under a positive pressure of nitrogen or argon.

[0039] Preparation examples

[0040] Example 1: Preparation of Compound 1

[0041]

[0042] Synthesis of Compound 1-2: In a reaction vessel, Compound 1-1 (1.7 g, 7 mmol), bis(pinacolato)diboron (11.5 g, 45.4 mmol), tris(dibenzylideneacetone)dipalladium(0) (2.1 g, 2.27 mmol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (2.7 g, 6.54 mmol), and potassium acetate (6.7 g, 68.1 mmol) were dissolved in 110 ml of 1,4-dioxane and stirred under reflux for 3 hours. After the reaction, the mixture was washed with distilled water and the organic layer was extracted with ethyl acetate. The organic layer was dried over magnesium sulfate, and after removing the solvent using a rotary evaporator, it was purified by column chromatography to obtain Compound 1-2 (2.2 g, 87%);

[0043] Synthesis of Compound 1: Compound 1-2 (4.1 g, 11.56 mmol), Compound 1-3 (4.7 g, 12.27 mmol), tetrakis(triphenylphosphine)palladium (400 mg, 0.35 mmol), potassium carbonate (4 g, 28.91 mmol), 57 mL of toluene, 14 mL of ethanol, and 14 mL of distilled water were added to a reaction vessel and stirred at 120 °C for 3 hours. After the reaction, the mixture was cooled to room temperature and the organic layer was extracted with ethyl acetate. The organic layer was dried over magnesium sulfate, and after removing the solvent using a rotary evaporator, it was purified by column chromatography to obtain Compound 1 (3.8 g, 61%), MS: 537.43.

[0044] Example 2: Preparation of Compound 3

[0045]

[0046] The synthesis of Compound 3-2 was the same as that of Compound 1-2, except that Compound 3-1 was used in place of Compound 1-1;

[0047] The synthesis of Compound 3 was the same as that of Compound 1, except that Compound 3-2 was used in place of Compound 1-2 and Compound 3-3 was used in place of Compound 1-3, MS: 510.39.

[0048] Example 3: Preparation of Compound 5

[0049]

[0050] The synthesis of Compound 5-2 was the same as that of Compound 1-2, except that Compound 5-1 was used in place of Compound 1-1;

[0051] The synthesis of Compound 5 is the same as that of Compound 1, except that Compound 5-2 is used to replace Compound 1-2, MS: 495.16.

[0052] Example 4: Preparation of Compound 16

[0053]

[0054] The synthesis of Compound 16-2 is the same as that of Compound 1-2, except that Compound 16-1 is used to replace Compound 1-1;

[0055] The synthesis of Compound 16 is the same as that of Compound 1, except that Compound 16-2 is used to replace Compound 1-2 and Compound 16-3 is used to replace Compound 1-3, MS: 765.52.

[0056] Example 5: Preparation of Compound 26

[0057]

[0058] The synthesis of Compound 26 is the same as that of Compound 1, except that Compound 16-2 is used to replace Compound 1-2 and Compound 26-1 is used to replace Compound 1-3, MS: 587.46.

[0059] Example 6: Preparation of Compound 29

[0060]

[0061] The synthesis of Compound 29-2 is the same as that of Compound 1-2, except that Compound 29-1 is used to replace Compound 1-1;

[0062] The synthesis of Compound 29 is the same as that of Compound 1, except that Compound 29-2 is used to replace Compound 1-2 and Compound 29-3 is used to replace Compound 1-3, MS: 573.44.

[0063] Example 7: Preparation of Compound 35

[0064]

[0065] The synthesis of Compound 35 is the same as that of Compound 1, except that Compound 5-2 is used to replace Compound 1-2 and Compound 35-1 is used to replace Compound 1-3, MS: 571.48.

[0066] Example 8: Preparation of Compound 41

[0067]

[0068] The synthesis of Compound 41-2 is the same as that of Compound 1-2, except that Compound 41-1 is used to replace Compound 1-1;

[0069] The synthesis of Compound 41 is the same as that of Compound 1, except that Compound 41-2 is used to replace Compound 1-2, MS: 613.51.

[0070] Example 9: Preparation of Compound 52

[0071]

[0072] The synthesis of Compound 52-2 is the same as that of Compound 1-2, except that Compound 52-1 is used to replace Compound 1-1;

[0073] The synthesis of Compound 52 is the same as that of Compound 1, except that Compound 52-2 is used to replace Compound 1-2 and Compound 52-3 is used to replace Compound 1-3, MS: 675.49.

[0074] Example 10: Preparation of Compound 65

[0075]

[0076] The synthesis of Compound 65-2 is the same as that of Compound 1-2, except that Compound 65-1 is used to replace Compound 1-1;

[0077] The synthesis of Compound 65 is the same as that of Compound 1, except that Compound 65-2 is used to replace Compound 1-2 and Compound 65-3 is used to replace Compound 1-3, MS: 647.21.

[0078] Example 11: Preparation of Compound 76

[0079]

[0080] The synthesis of Compound 76 is the same as that of Compound 1, except that Compound 41-2 is used to replace Compound 1-2 and Compound 76-1 is used to replace Compound 1-3, MS: 638.48.

[0081] Example 12: Preparation of Compound 81

[0082]

[0083] The synthesis of Compound 81-2 is the same as that of Compound 1-2, except that Compound 81-1 is used to replace Compound 1-1;

[0084] The synthesis of compound 81 is the same as that of compound 1, except that compound 81-2 is used to replace compound 1-2, MS: 689.24.

[0085] Example 13: Preparation of compound 100

[0086]

[0087] The synthesis of compound 100-2 is the same as that of compound 1-2, except that compound 100-1 is used to replace compound 1-1;

[0088] The synthesis of compound 100 is the same as that of compound 1, except that compound 100-2 is used to replace compound 1-2 and compound 100-3 is used to replace compound 1-3, MS: 875.55.

[0089] Example 14: Preparation of compound 111

[0090]

[0091] The synthesis of compound 111 is the same as that of compound 1, except that compound 81-2 is used to replace compound 1-2 and compound 35-1 is used to replace compound 1-3, MS: 765.30.

[0092] Example 15: Preparation of compound 123

[0093]

[0094] The synthesis of compound 123-2 is the same as that of compound 1-2, except that compound 123-1 is used to replace compound 1-1;

[0095] The synthesis of compound 123 is the same as that of compound 1, except that compound 123-2 is used to replace compound 1-2, MS: 737.24.

[0096] Example 16: Preparation of compound 130

[0097]

[0098] The synthesis of compound 130-2 is the same as that of compound 1-2, except that compound 130-1 is used to replace compound 1-1;

[0099] The synthesis of compound 130 is the same as that of compound 1, except that compound 130-2 is used to replace compound 1-2 and compound 130-3 is used to replace compound 1-3, MS: 799.26.

[0100] Example 17: Preparation of Compound 138

[0101]

[0102] Compound 138 was synthesized in the same manner as Compound 1, except that Compound 123-2 was used in place of Compound 1-2, and Compound 16-3 was used in place of Compound 1-3. MS: 965.34

[0103] Example 18: Preparation of Compound 146

[0104]

[0105] Compound 146-2 was synthesized in the same manner as Compound 1-2, except that Compound 146-1 was used in place of Compound 1-1;

[0106] Compound 146 was synthesized in the same manner as Compound 1, except that Compound 146-2 was used in place of Compound 1-2, and Compound 26-1 was used in place of Compound 1-3. MS: 815.53

[0107] Example 19: Preparation of Compound 156

[0108]

[0109] Compound 156 was synthesized in the same manner as Compound 1, except that Compound 146-2 was used in place of Compound 1-2, and Compound 156-3 was used in place of Compound 1-3. MS: 689.49

[0110] Example 20: Preparation of Compound 162

[0111]

[0112] Compound 162-2 was synthesized in the same manner as Compound 1-2, except that Compound 162-1 was used in place of Compound 1-1;

[0113] Compound 162 was synthesized in the same manner as Compound 1, except that Compound 162-2 was used in place of Compound 1-2. MS: 751.51

[0114] Example 21: Preparation of Compound 170

[0115]

[0116] The synthesis of Compound 170 is the same as that of Compound 1, except that Compound 195-2 is used to replace Compound 1-2, and Compound 130-3 is used to replace Compound 1-3. MS: 799.52.

[0117] Example 22: Preparation of Compound 176

[0118]

[0119] The synthesis of Compound 176-2 is the same as that of Compound 1-2, except that Compound 176-1 is used to replace Compound 1-1;

[0120] The synthesis of Compound 176 is the same as that of Compound 1, except that Compound 176-2 is used to replace Compound 1-2, and Compound 176-3 is used to replace Compound 1-3. MS: 993.63.

[0121] Example 23: Preparation of Compound 183

[0122]

[0123] The synthesis of Compound 183-2 is the same as that of Compound 1-2, except that Compound 183-1 is used to replace Compound 1-1;

[0124] The synthesis of Compound 183 is the same as that of Compound 1, except that Compound 183-2 is used to replace Compound 1-2, and Compound 65-2 is used to replace Compound 1-3. MS: 813.28.

[0125] Example 24: Preparation of Compound 187

[0126]

[0127] The synthesis of Compound 187 is the same as that of Compound 1, except that Compound 162-2 is used to replace Compound 1-2, and Compound 26-1 is used to replace Compound 1-3. MS: 801.54.

[0128] Example 25: Preparation of Compound 195

[0129]

[0130] The synthesis of Compound 195-2 is the same as that of Compound 1-2, except that Compound 195-1 is used to replace Compound 1-1;

[0131] The synthesis of Compound 195 is the same as that of Compound 1, except that Compound 195-2 is used to replace Compound 1-2, and Compound 195-3 is used to replace Compound 1-3. MS: 724.23.

[0132] Example 26: Preparation of Compound 201

[0133]

[0134] The synthesis of Compound 201-2 is the same as that of Compound 1-2, except that Compound 201-1 is used to replace Compound 1-1;

[0135] The synthesis of Compound 201 is the same as that of Compound 1, except that Compound 201-2 is used to replace Compound 1-2. MS: 689.52.

[0136] Example 27: Preparation of Compound 218

[0137]

[0138] The synthesis of Compound 218-2 is the same as that of Compound 1-2, except that Compound 218-1 is used to replace Compound 1-1;

[0139] The synthesis of Compound 218 is the same as that of Compound 1, except that Compound 218-2 is used to replace Compound 1-2, and Compound 16-3 is used to replace Compound 1-3. MS: 889.57.

[0140] Example 28: Preparation of Compound 223

[0141]

[0142] The synthesis of Compound 223 is the same as that of Compound 1, except that Compound 218-2 is used to replace Compound 1-2, and Compound 65-2 is used to replace Compound 1-3. MS: 737.50.

[0143] Example 29: Preparation of Compound 237

[0144]

[0145] The synthesis of Compound 237-2 is the same as that of Compound 1-2, except that Compound 237-1 is used to replace Compound 1-1;

[0146] The synthesis of Compound 237 is the same as that of Compound 1, except that Compound 237-2 is used to replace Compound 1-2, and Compound 156-3 is used to replace Compound 1-3. MS: 599.45.

[0147] In addition, it should be noted that other compounds of this application can be obtained by referring to the preparation methods of the above-listed examples, so they will not be listed one by one here.

[0148] Device Examples

[0149] Preparation of Device Example 1:

[0150] Put the glass substrate with ITO (indium tin oxide) coated thereon with a thickness of as a thin film into distilled water in which a cleaning agent is dissolved, and perform ultrasonic cleaning. After cleaning the ITO for 30 minutes, repeat ultrasonic cleaning twice with distilled water for 10 minutes, then perform ultrasonic cleaning on the substrate with isopropyl alcohol, acetone and methanol solvents, dry it, transfer it to a plasma cleaner for cleaning for 5 minutes, and then transfer it to a vacuum depositor;

[0151] On the ITO transparent electrode, thermally vacuum deposit Compound [HI] to a thickness to form a hole injection layer; on the hole injection layer, vacuum deposit Compound [HT] to to form a hole transport layer; on the hole transport layer, vacuum deposit Compound [BH] and Compound [BD] at a ratio of 97:3 to a thickness to form a light-emitting layer; on the light-emitting layer, vacuum deposit Compound 1 and Compound [LiQ] (lithium quinolate) at a ratio of 1:1 to form a thickness of an electron transport layer; on the electron transport layer, deposit ytterbium (Yb) and magnesium silver (1:9) sequentially to thicknesses of and respectively to form a cathode. The vacuum degree during deposition is maintained at 1×10 -7 Torr to 5×10 -8 Torr.

[0152] Preparation of Device Examples 2-29:

[0153] When forming the electron transport layer, replace Compound 1 in Example 1 with the compounds shown in Table 1, and prepare the organic electroluminescent device using the same method as in Example 1.

[0154] Preparation of Device Comparative Example 1:

[0155] Prepare the organic electroluminescent device using the same method as in Example 1, except that the comparative compound ref is used to replace Compound 1 when forming the electron transport layer.

[0156] The structures of the compounds used in the above preparation process are as follows:

[0157]

[0158] The LUMO values of the compounds in the device examples were calculated by Gaussian calculation software, and the driving voltages and current efficiencies of the device examples and the comparative examples were measured at a current density of 10 mA / cm 2 and the time (LT97) required for the brightness to decrease to 97% of the initial brightness was measured at a current density of 50 mA / cm 2 . The results are shown in Table 1 below:

[0159] Table 1

[0160]

[0161]

[0162] As can be seen from the above table, compared with the comparative compound ref, the compounds corresponding to Examples 1-29 have lower LUMO values. When used as the electron transport layer material of an organic electroluminescent device, the electron injection and transport barrier can be further reduced, the driving voltage can be reduced, the electron mobility can be increased, and the carrier transport can reach equilibrium. Furthermore, the devices prepared from this series of compounds have higher current efficiency and service life compared with Comparative Example 1. Therefore, this series of compounds is an electron transport layer material with good performance.

Claims

1. An electron transport layer compound containing a cyclohexyl group, characterized in that: It has the structure shown in the following general formula I: In the general formula I, Ar1, Ar2, and Ar3 are each independently selected from substituted or unsubstituted C6 to C 36 Aryl, substituted or unsubstituted C6~C 36 A heteroaryl group or a structure shown in the following formula I-1, and at least one of Ar1, Ar2, and Ar3 has a structure shown in the following formula I-1: In formula I-1, L is selected from substituted or unsubstituted C6 to C 36 Aryl, substituted or unsubstituted C6~C 36 The heteroaryl group, R is independently selected from C1 to C 18 wherein n is an integer from 1 to 5; when there is a substitution, the substituent is selected from pyridyl, cyano, and alkyl.

2. The cyclohexyl-containing electron transport layer compound according to claim 1, characterized in that: Ar1, Ar2, Ar3 are each independently selected from C6 to C 18 An aromatic group or a structure represented by formula I-1.

3. The cyclohexyl-containing electron transport layer compound according to claim 1, characterized in that: L is selected from C6~C 24 The aromatic group.

4. The cyclohexyl-containing electron transport layer compound according to claim 1, characterized in that: R is independently selected from C1-C6 alkyl groups.

5. The cyclohexyl-containing electron transport layer compound according to claim 1, characterized in that: n is 1 or 2.

6. The cyclohexyl-containing electron transport layer compound according to claim 1, characterized in that: One of Ar1, Ar2 and Ar3 has a structure represented by Formula I-1.

7. The cyclohexyl-containing electron transport layer compound according to claim 1, characterized in that: Its structure is one of the following:

8. An organic electroluminescent device comprising a first electrode, a second electrode and an organic material layer disposed therebetween, characterized in that: The organic material layer comprises an electron transport layer, and the electron transport layer is prepared from the electron transport layer compound containing cyclohexyl group according to any one of claims 1 to 7.

9. The organic electroluminescent device according to claim 8, characterized in that: The organic electroluminescent device is used to manufacture display devices, lighting sources, signal lights, and signboards. The display devices include mobile phone display screens, computer display screens, television display screens, smart watch display screens, smart car display panels, and VR or AR helmet display screens.

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