# US 11,898,074 B2 · Blue thermally activated delayed fluorescence material, synthesis method thereof, and use thereof

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- Number: US 11,898,074 B2
- Document ID: US11898074B2
- Status: Granted
- Kind: B2
- Application number: 16/973,824
- Filed: 2019-09-10
- Published: 2021-08-19
- Granted: 2024-02-13
- Earliest claimed: 2019-05-31
- Assignees: Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Applicants: Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Inventors: Jiajia Luo; Jinchang Huang; Lin Yang; Qu Zhang
- Web page: https://patentgrep.com/patent/US11898074B2

## CPC

- C09K 11/06: containing organic luminescent materials
- H10K 85/40: Organosilicon compounds, e.g. TIPS pentacene
- H10K 85/657: {Polycyclic condensed heteroaromatic hydrocarbons}
- H10K 85/6572: {comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole}
- C09K 2211/1014: bridged by heteroatoms, e.g. N, P, Si or B
- C09K 2211/1033: with oxygen
- C09K 2211/104: with other heteroatoms
- H10K 50/11: characterised by the electroluminescent [EL] layers
- H10K 50/16: Electron transporting layers
- H10K 2101/20: Delayed fluorescence emission
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

The present disclosure relates to the field of organic light-emitting materials, and more particularly, to a blue thermally activated delayed fluorescence material, a synthesis method thereof, and use thereof. The blue thermally activated delayed fluorescence material has a following structural formula: the present disclosure provides a novel blue thermally activated delayed fluorescence material which has a lower singlet triplet energy level difference, a high RISC rate constant (kRISC), and a high photoluminescence quantum yield (PLQY) by finely adjusting a structure of electron acceptor units, making them have different abilities to accept electrons, thereby realizing fine adjustment of spectrum in the deep blue range.

## Claims

### Claim 1

A blue thermally activated delayed fluorescence material, having a following structural formula:
wherein, R is selected from one of following structural formulas:

### Claim 2

A synthesis method of a blue thermally activated delayed fluorescence material, comprising following steps: under an inert gas environment, performing a Buchwald-Hartwig coupling reaction between a raw material 1 and a raw material 2 under an effect of a palladium catalyst to obtain the blue thermally activated delayed fluorescence material;
wherein, the raw material 1 has a following structural formula:
the raw material 2 is selected from one of 9,9-diphenyl-9,10-dihydroacridine, phenoxazine, 3,6-dimethyl-9H-carbazole, 10H-spiro[acridine-9,9′-fluorene], 9,9-dimethyl-9,10-dihydroacridine, 9,10-dihydro-9,9-diphenylsila acridine, 3,7-dimethoxy-10H-phenoxazine, 10H-silaspiro[acridine-9,9′-fluorene], 7H-benzo[C]phenoxazine, 9-phenyl-7H-benzo[C]phenoxazine, 3, 6-di-tert-butyl-9H-carbazole, 1,3,6,8-tetramethyl-9H-carbazole, or 2-(tert-butyl)-5H-benzo[b]carbazole; and
a molar ratio of the raw material 1 to the raw material 2 ranges from 1:2 to 1:6.

### Claim 3 (depends on 2)

The synthesis method of the blue thermally activated delayed fluorescence material according to claim 2, wherein a reaction temperature of the Buchwald-Hartwig coupling reaction ranges from 80° C. to 160° C., and a reaction time thereof ranges from 12 hours to 48 hours.

### Claim 4 (depends on 2)

The synthesis method of the blue thermally activated delayed fluorescence material according to claim 2, wherein a reaction solvent of the Buchwald-Hartwig coupling reaction is dehydrated and deoxygenated toluene; the palladium catalyst is selected from one of palladium acetate, palladium nitrate, palladium chloride, or palladium sulfate.

### Claim 5 (depends on 2)

The synthesis method of the blue thermally activated delayed fluorescence material according to claim 2, wherein, after finishing the Buchwald-Hartwig coupling reaction, a reaction product is subjected to cooling, extraction, column chromatography separation, and purification in sequence to obtain the blue thermally activated delayed fluorescence material.

### Claim 6

An organic electroluminescent device comprising a blue thermally activated delayed fluorescence material;
wherein the blue thermally activated delayed fluorescence material has the following structural formula:
wherein, R is selected from one of the following structural formulas:

### Claim 7 (depends on 6)

The organic electroluminescent device according to claim 6, wherein the organic electroluminescent device is an electrothermally activated delayed fluorescent device.

### Claim 8 (depends on 7)

The organic electroluminescent device according to claim 7, wherein the electrothermally activated delayed fluorescent device comprises a substrate layer, a light-emitting layer, and a cathode layer in a stack, and a light-emitting material of the light-emitting layer is the blue thermally activated delayed fluorescence material.

### Claim 9 (depends on 8)

The organic electroluminescent device according to claim 8, wherein the electrothermally activated delayed fluorescent device further comprises a hole injection layer disposed on the substrate layer, a transport layer disposed on the hole injection layer, and an electron transport layer disposed between the light-emitting layer and the cathode layer.