ORGANIC ELECTROLUMINESCENT MATERIAL AND APPLICATION THEREOF IN OPTOELECTRONIC DEVICES

Abstract

The invention provides an organic electroluminescent material and application thereof in optoelectronic devices. The organic electroluminescent material according to the invention having the structure of Formula (I), the compound of which contains a unit formed by imidazole and indenopyrrole, with its spiro structure molecule that is beneficial to inhibit the stacking between molecules. The compound has better thermal stability and will be applied to organic electroluminescent devices with characteristics such as luminous efficiency and color purity, has the potential to be applied to organic electroluminescent devices. The invention further provides an optoelectronic device including a cathode, an anode, and an organic layer. The organic layer is one or more of a hole injection layer, a hole transport layer, a light-emitting layer, a hole-blocking layer, an electron injection layer, and an electron transport layer. At least one layer of the organic layer contains the compound having Formula (I).

##STR00001##

Claims

1. An organic electroluminescent material having a chemical structure of Formula (I), ##STR00028## wherein L is a single bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, or a substituted or unsubstituted pyridylene group, Ar is one of the following groups: ##STR00029## B is selected from O, S and Se, X.sub.1-X.sub.8 are independently selected from N or CR, and each six-membered ring contains at most one N atom. R is independently selected from one of a hydrogen atom, a deuterium atom, a halogen, an alkyl group, a heteroalkyl group, an aryl group, a heteroaryl group, an aryloxy group.

2. The organic electroluminescent material according to claim 1, wherein L is a single bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, or a substituted or unsubstituted pyridylene group, Ar is one of the following groups: ##STR00030## where B is selected from O and S, X.sub.1-X.sub.8 are independently selected from N or CR, and each six-membered ring contains at most one N atom, R is independently selected from one of a hydrogen atom, a deuterium atom, an alkyl group, and an aryl group.

3. The organic electroluminescent material according to claim 2, wherein L is a single bond or a phenylene group, Ar is one of the following groups: ##STR00031## where B is selected from O and S, one of X.sub.1-X.sub.8 is N, and the rest are CH.

4. The organic electroluminescent material according to claim 3, wherein L is a single bond, Ar is one of the following groups: ##STR00032## where B is selected from O and S, one of X.sub.1-X.sub.8 is N, and the rest are CH.

5. The organic electroluminescent material according to claim 2, wherein L is a single bond, Ar is one of the following groups: ##STR00033## where B is selected from O and S, X.sub.1-X.sub.8 are CH.

6. An organic electroluminescent material according to claim 1, comprising the following compounds: ##STR00034## ##STR00035## ##STR00036## ##STR00037## ##STR00038## ##STR00039## ##STR00040## ##STR00041## ##STR00042##

7. A preparation method for said organic electroluminescent material according to any one of claims 1-6, comprising the following steps: S1: providing Compound a and Y-L-Ar, where Y is halogen; ##STR00043## S2: heating said Compound a and Y-L-Ar, Pd(OAc).sub.2, PPh.sub.3, K.sub.2CO.sub.3 and DMAc to 150° C. to react under a nitrogen atmosphere to obtain said compound represented by Formula (I).

8. The preparation method according to claim 7, wherein said Y is chlorine or bromine.

9. The preparation method according to claim 7, wherein the preparation method of said Compound a comprises the following steps: A) reacting Compound a-1 with o-dihalopyrazine to obtain Compound a-2, B) reacting said Compound a-2 with imidazole to obtain Compound a-3, C) cyclizing said Compound a-3 to obtain said Compound a, ##STR00044##

10. The preparation method according to claim 9, wherein said o-dihalopyrazine is o-dibromopyrazine.

11. The preparation method according to claim 10, wherein the reaction formula for preparing said Compound a is as follows: ##STR00045##

12. Application of said organic electroluminescent material according to any one of claims 1-6 in organic electroluminescent devices, mechanoluminescent devices, organic field effect transistors, organic solar cells and chemical sensors.

13. An organic electroluminescent device comprising a cathode, an anode, and an organic layer, wherein said organic layer is one or more of a hole injection layer, a hole transport layer, a light-emitting layer, a hole-blocking layer, an electron injection layer, and an electron transport layer, said organic layer contains said organic electroluminescent material according to any one of claims 1-6.

14. The organic electroluminescent device according to claim 13, wherein the layer where said organic electroluminescent material according to any one of claims 1-6 is located is a light-emitting layer or an electron transport layer.

15. The organic electroluminescent device according to claim 13, wherein the total thickness of said organic layer is 1-1000 nm, said organic layer is formed into a thin film by vapor deposition or solution method.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1 is a structural diagram of the organic electroluminescent device according to invention.

[0045] 10—glass substrate, 20—anode, 30—hole injection layer, 40—hole transport layer, 50—light-emitting layer, 60—electron transport layer, 70—electron injection layer, 80—cathode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] In order to describe the invention in more detail, the following examples are given, but not limited thereto.

[0047] Compound 1-1 and Compound 13-1 that are not specifically mentioned are commercially available compounds.

Example 1

Synthetizing Compound 1

[0048] ##STR00019##

Synthetizing Intermediate a-2

[0049] The Compound a-1 (6.10 g, 20.0 mmol) (synthesized by reference to Literature Org. Lett., 2010, 12, 296-299), o-dibromobenzene (9.44 g, 40.0 mmol), CuI (380 mg, 2.0 mmol), trans-1,2-cyclohexanediamine (456 mg, 4.0 mmol), K.sub.3PO.sub.4 (12.74 g, 60.0 mmol) and xylene (100 mL) are sequentially added to the Schlenk tube under a nitrogen atmosphere, heated to 90° C. and react for 24 hours. After cooling to room temperature, the above reaction solution is added to water, extracted by dichloromethane three times, and then organic phases are combined. After the organic phase is dried by anhydrous sodium sulfate, and spun off the solvent, and the residue is separated by column chromatography to obtain a grayish white solid (5.1 g, the yield is 55%).

Synthetizing Intermediate a-3

[0050] The Compound a-2 (5.0 g, 10.9 mmol), imidazole (1.36 g, 20.0 mmol), CuI (380 mg, 2.0 mmol), K.sub.2CO.sub.3 (8.50 g, 40.0 mmol) and xylene (100 mL) are sequentially added to the Schlenk tube under a nitrogen atmosphere, heated to 90° C. and react for 24 hours. After cooling to room temperature, the above reaction solution is added to water, extracted by dichloromethane three times, and then organic phases are combined. After the organic phase is dried by anhydrous sodium sulfate, and spun off the solvent, and the residue is separated by column chromatography to obtain a light yellow solid (3.2 g, the yield is 66%).

Synthetizing Intermediate a

[0051] The Compound a-3 (3.0 g, 6.7 mmol) is dissolved in tetrahydrofuran (30 mL) under a nitrogen atmosphere, and cooled to −40° C., then added to by sec-butyllithium s-BuLi (1.2 eq) dropwise with stirring for 30 minutes, then iodine (1.1 eq) is added, after stirring for 30 minutes, the temperature thereof rises to room temperature, then stirring continues for 1 hour. The above reaction solution is added to water, extracted by dichloromethane three times, and then organic phases are combined. After the organic phase is dried by anhydrous sodium sulfate, and spun off the solvent to obtain a light yellow solid. The above solid is dis solved in tetrahydrofuran (20 mL), dichlorodi-tert-butyl(4-Dimethylaminophenyl)-phosphine palladium PdCl.sub.2(AMPhos).sub.2 (0.05 eq) and potassium carbonate aqueous solution (2M, 4 mL) are added, and refluxed overnight under a nitrogen atmosphere. After cooling to room temperature, the above reaction solution is added to water, extracted by dichloromethane three times, and then organic phases are combined. After the organic phase is dried by anhydrous sodium sulfate, and spun off the solvent, and the residue is separated by column chromatography to obtain a light yellow solid (1.6 g, the yield is 53%).

Synthetizing Compound 1

[0052] The Compound a (2.1 g, 4.7 mmol), Compound 1-1 (5.8 g, 23.4 mmol), Pd(OAc).sub.2 (105 mg, 0.47 mmol), PPh.sub.3 (380 mg, 1.4 mmol), K.sub.2CO.sub.3 (1.38 g, 10 mmol) and DMAc (20 mL) are sequentially added to the Schlenk tube under a nitrogen atmosphere, heated to 150° C. and react for 24 hours. After cooling to room temperature, the above reaction solution is added to water, extracted by dichloromethane three times, and then organic phases are combined. After the organic phase is dried by anhydrous sodium sulfate, and spun off the solvent, and the residue is separated by column chromatography to obtain a light yellow solid (1.5 g, the yield is 52%). ESI-MS (m/z): 614.3 (M+1).

Example 2

Synthetizing Compound 9

[0053] ##STR00020##

[0054] The Compound a (1.6 g, 3.6 mmol), the Compound 9-1 (3.7 g, 18.0 mmol) (synthesized by reference to CN102449107), Pd(OAc).sub.2 (80 mg, 0.36 mmol), PPh.sub.3 (190 mg, 0.72 mmol), K.sub.2CO.sub.3 (1.38 g, 10 mmol) and DMAc (20 mL) are sequentially added to the Schlenk tube under a nitrogen atmosphere, heated to 150° C. and react for 24 hours. After cooling to room temperature, the above reaction solution is added to water, extracted by dichloromethane three times, and then organic phases are combined. After the organic phase is dried by anhydrous sodium sulfate, and spun off the solvent, and the residue is separated by column chromatography to obtain a light yellow solid (700 mg, the yield is 32%). ESI-MS (m/z): 615.0 (M+1).

Example 3

Synthetizing Compound 11

[0055] ##STR00021##

[0056] The Intermediate 11-1 (synthesized by reference to Literature Dyes Pigm., 2013, 99, 390-394) is used to replace the Intermediate 9-1, and the Compound 11 is prepared by reference to the method for synthetizing the Compound 9 to obtain a light yellow solid (700 mg, the yield is 33%). ESI-MS (m/z): 631.3 (M+1).

Example 4

Synthetizing Compound 13

[0057] ##STR00022##

[0058] The Intermediate 13-1 is used to replace the Intermediate 9-1, and the Compound 13 is prepared by reference to the method for synthetizing the Compound 9 to obtain a light yellow solid (1.1 g, the yield is 50%). ESI-MS (m/z): 630.0 (M+1).

Example 5

Synthetizing Compound 22

[0059] ##STR00023##

[0060] The Intermediate 22-1 (synthesized by reference to CN105585555) is used to replace Intermediate 9-1, and the Compound 22 is prepared by reference to the method for synthetizing the Compound 9 to obtain a light yellow solid (800 mg, the yield is 47%). ESI-MS (m/z): 690.0 (M+1).

Example 6

Synthetizing Compound 27

[0061] ##STR00024##

[0062] The Intermediate 27-1 (synthesized by reference to US2012/256169) is used to replace the Intermediate 9-1, and the Compound 27 is prepared by reference to the method for synthetizing the Compound 9 to obtain a light yellow solid (600 mg, the yield is 50%). ESI-MS (m/z): 706.2 (M+1).

Example 7

Synthetizing Compound 30

[0063] ##STR00025##

[0064] The Intermediate 30-1 (synthesized by reference to CN107686484) is used to replace the Intermediate 9-1, and the Compound 30 is prepared by reference to the method for synthetizing the Compound 9 to obtain a light yellow solid (750 mg, the yield is 43%). ESI-MS (m/z): 689.3 (M+1).

Example 8

Synthetizing Compound 36

[0065] ##STR00026##

[0066] The Intermediate 36-1 (synthesized by reference to Literature Chem. Mater., 2013, 25, 3758-3765) is used to replace the Intermediate 9-1, and the Compound 36 is prepared by reference to the method for synthetizing the Compound 9 to obtain a light yellow solid (660 mg, the yield is 52%). ESI-MS (m/z): 765.1 (M+1).

Examples 9-16

[0067] The organic light-emitting material according to the invention is used to prepare an electroluminescent device, the structure of which is shown in FIG. 1.

[0068] First, washing the transparent conductive ITO glass substrate 10 (with an anode 20 on it) sequentially by detergent solution, deionized water, ethanol, acetone, and deionized water, and then treating it with oxygen plasma for 30 seconds.

[0069] Then, evaporatively depositing 10 nm thick HATCN on the ITO as the hole injection layer 30.

[0070] Then, evaporatively depositing the compound TAPC to form a 40 nm thick hole transport layer 40.

[0071] Then, evaporatively depositing a 30 nm thick light-emitting layer 50 on the hole transport layer. The light-emitting layer is composed of Ir(PPy).sub.3 (10%) and the compound product (90%) in Examples 1-8 by co-doping.

[0072] Then, evaporatively depositing a 50 nm thick TmPyPb on the light-emitting layer as the electron transport layer 60.

[0073] Finally, evaporatively depositing a 1 nm thick LiF as the electron injection layer 70 and a 100 nm thick Al as the device cathode 80.

Comparative Example

[0074] CBP is used to replace the above-mentioned compound in the invention, an organic light-emitting device is prepared according to the same method.

[0075] The structure presented in the device is as bellows.

##STR00027##

[0076] The efficiency of the organic electroluminescent devices in Examples 9-17 and Comparative Example at a current density of 10 mA/cm.sup.2 is as follows:

TABLE-US-00001 Light-emitting External Luminous device Compound quantum efficiency color 9 1 15.6 Green 10 9 14.7 Green 11 11 14.5 Green 12 13 15.2 Green 13 22 16.4 Green 14 27 16.2 Green 15 30 16.8 Green 16 36 17.2 Green Comparative CBP 12.7 Green Example

[0077] Under the same conditions, the efficiency of organic electroluminescent devices prepared by using the compound of the invention is better than that of the comparative example. The compound of the invention has better stability, and the device manufactured by using the compound of the invention has better color purity and efficiency, with great significance for optimizing the performance of organic optoelectronic devices.

[0078] The various embodiments described above are only examples, and are not intended to limit the scope of the invention. Without departing from the essence of the invention, various materials and structures in the invention can be replaced by other materials and structures. It should be understood that a skilled person in the art can make many modifications and changes according to the idea of the invention without creative effort. Therefore, the technical solutions that can be obtained by the skilled person through analysis, ratiocination or partial research on the basis of the prior art should be within the protection scope defined by the claims.