EP-4741407-A1 - PYRIDINOCARBENE-BASED TETRADENTATE CYCLOMETALATED PLATINUM (II) COMPLEX AND USE THEREOF

Abstract

A pyridine-fused carbene-based tetradentate cyclometalated platinum(II) complex is provided. Compared to a benzo-fused carbene-based platinum(II) complex, since a pyridine-fused carbene exhibits stronger an electron-withdrawing capacity, an excited state of a pyridine-fused carbene-based tetradentate cyclometalated platinum(II) complex is endowed with a greater proportion of metal-to-pyridine-fused carbene charge transfer states ( 3 MLCT). This facilitates an increase in radiative rate, thereby enhancing lifetime of a device. Materials provided in the present disclosure all exhibit excellent chemical and thermal stability, facilitating the fabrication of vacuum-evaporated OLED devices. Organic electroluminescent devices fabricated with compounds of the present disclosure as light-emitting layers demonstrate significant improvements in both current efficiency and lifetime, while also markedly reducing a turn-on voltage. Combining the compounds of the present disclosure with fluorescent dopant materials (boron-containing compounds) can balance transport of holes and electrons, enable more efficient energy transfer between host and guest materials, and enhance light color purity of devices.

Inventors

• LI, GUIJIE
• TONG, JIEYING
• ZHAN, FENG
• CHEN, JIANQIANG
• SHE, YUANBIN
• WU, KONGWU

Assignees

• Zhejiang University of Technology
• Zhejiang Huaxian Photoelectricity Technology Co., Ltd

Dates

Publication Date

20260513

Application Date

20231204

Claims (14)

1. A pyridine-fused carbene-based tetradentate cyclometalated platinum(II) complex, characterized by having a general structure shown in formula (I): wherein in formula (I), R 1 -R 5 each independently represent from mono to maximum allowable substitution, or no substitution; R 1 -R 5 are each independently selected from the group consisting of: hydrogen, deuterium (D), C1-C30 alkyl, C1-C30 deuterated alkyl, C6-C60 aryl, C6-C30 aryl silane, and combinations thereof; and R is selected from the group consisting of hydrogen, deuterium, C1-C30 alkyl, C1-C30 cycloalkyl, C1-C30 deuterated alkyl, C6-C60 aryl, C6-C30 fused-ring aryl, and combinations thereof.
2. The tetradentate cyclometalated platinum(II) complex according to claim 1, characterized in that , R 1 -R 5 are each independently selected from hydrogen, deuterium, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, n-hexyl, isohexyl, sec-hexyl, tert-hexyl, n-heptyl, isoheptyl, sec-heptyl, tert-heptyl, n-octyl, iso-octyl, sec-octyl, tert-octyl, n-nonyl, iso-nonyl, sec-nonyl, tert-nonyl, n-decyl, isodecyl, sec-decyl, tert-decyl, phenyl, triphenylsilane, and combinations thereof.
3. The tetradentate cyclometalated platinum(II) complex according to claim 1, characterized in that , R is selected from amantadine, tert-butyl, tert-butylphenyl, and groups represented by following structural formulas: wherein R 6 represents from mono to maximum number allowable substitution, or no substitution; R 6 is selected from hydrogen, C1-C20 alkyl and C1-C20 deuterated alkyl; and R a and R b are identically or independently selected from C3-C30 alkyl, C1-C20 deuterated alkyl, C5-C30 cycloalkyl, C6-C30 aryl, and combinations thereof.
4. The tetradentate cyclometalated platinum(II) complex according to claim 3, characterized in that , R 6 is selected from hydrogen, methyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, D and CD 3 ; and R a and R b are identically or independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, n-hexyl, iso-hexyl, sec-hexyl, tert-hexyl, phenyl, and combinations thereof.
5. The tetradentate cyclometalated platinum(II) complex according to any one of claims 1 to 4 , characterized in that , the pyridine-fused carbene-based tetradentate cyclometalated platinum(II) complex is any one selected from chemical structures shown below, wherein D represents deuterium, and Ph represents phenyl:
6. An application of the tetradentate cyclometalated platinum(II) complex according to any one of claims 1 to 5 in an electronic device, wherein the electronic device comprises one or more of an organic electroluminescent device, an organic integrated circuit, an organic field-effect transistor, an organic thin-film transistor, an organic light-emitting transistor, an organic solar cell, an organic optical detector, an organophotoreceptor, an organic field-quench device, a light-emitting electrochemical cell and an organic laser diode.
7. An organic electroluminescent device, characterized in that , the organic electroluminescent device comprises a cathode, an anode and an organic functional layer between the cathode and the anode, wherein the organic functional layer contains the tetradentate cyclometalated platinum(II) complex according to any one of claims 1 to 5.
8. An organic electroluminescent device, characterized in that , the organic functional layer includes a light-emitting layer, wherein the light-emitting layer contains the tetradentate cyclometalated platinum(II) complex according to any one of claims 1 to 5.
9. The organic electroluminescent device according to claim 7, characterized in that , the light-emitting layer further includes a fluorescent dopant material, wherein the fluorescent dopant material is a boron-containing compound.
10. An organic optoelectronic device, characterized in that , the organic optoelectronic device comprises: a substrate layer, a first electrode disposed on the substrate, an organic light-emitting functional layer disposed on the first electrode, and a second electrode disposed on the organic light-emitting functional layer, wherein the organic light-emitting functional layer contains the tetradentate cyclometalated platinum(II) complex according to any one of claims 1 to 5.
11. The organic optoelectronic device according to claim 10 , characterized in that , the organic light-emitting functional layer further contains a fluorescent dopant material, wherein the fluorescent dopant material is a boron-containing organic molecular light-emitting material.
12. A composition, characterized in that , the composition contains the tetradentate platinum(II) complex according to any one of claims 1 to 5.
13. A formulation, characterized in that , the formulation contains the tetradentate platinum(II) complex according to any one of claims 1 to 5.
14. A display or lighting apparatus, characterized in that , the apparatus comprises at least one organic electroluminescent device each according to any one of claims 7 to 9.

Description

TECHNICAL FIELD The present disclosure relates to the field of organic electroluminescence, specifically to a pyridine-fused carbene-based tetradentate cyclometalated platinum(II) complex and an application thereof. BACKGROUND Organic light-emitting diodes (OLEDs) represent a new generation of full-color display and lighting technology. As self-luminous devices, OLEDs offer advantages such as no requirement for backlight, low drive voltage, quick response, high resolution and contrast, wide viewing angle and excellent low-temperature performance; and OLED devices may be fabricated to be thin and into flexible structures. In additional, OLEDs further offer advantages such as low production costs, a simple manufacturing process and suitability for large-format products. The core of the development of OLEDs lies in design and development of light-emitting materials. Red OLEDs and green OLEDs have essentially reached the standards for commercial application. However, due to long lifetime of triplet excitons and wide bandgaps of blue light-emitting materials, blue OLED devices are prone to triplet exciton accumulation and cleavage of organic molecular chemical bonds at high brightness levels. This severely compromises the stability of the devices, thereby significantly limiting the development and application of blue OLEDs. Research on organic blue light-emitting materials of OLEDs, both domestically and internationally, is developing along multiple pathways. Currently, light-emitting layers of OLED devices almost exclusively employs a host-guest light-emitting system, i.e., doping a host material with a guest light-emitting material. An energy gap of the host material is typically higher than that of the guest light-emitting material, such that energy is transferred from the host material to the guest light-emitting material, thereby leading to excitation and subsequent light emission of the guest light-emitting material. Common organic phosphorescent guest materials are predominantly complexes of heavy metals such as iridium(III), platinum(II) and palladium(II). Currently, heavy-metal phosphorescent organic complexes in use are mainly cyclometalated iridium(III) complex molecules, whose variety is limited. In contrast, preparation of platinum(II) complex phosphorescent materials exhibits high platinum utilization, which may further reduce preparation costs of the platinum(II) complex phosphorescent materials. The preparation costs of the platinum(II) complex phosphorescent materials are significantly lower than those of iridium(III) complex phosphorescent materials. However, there are still some technical challenges in the development of platinum complex materials and devices, and improving device efficiency and lifetime remains an important research topic. Therefore, novel phosphorescent platinum(II) metal complexes need to be developed. SUMMARY In view of the above, the present disclosure aims to provide a pyridine-fused carbene-based tetradentate cyclometalated platinum(II) complex and an application thereof. An organic electroluminescent device fabricated by using the pyridine-fused carbene-based tetradentate cyclometalated platinum(II) complex of the present disclosure as a light-emitting layer may be enabled to exhibit excellent performance, current efficiency of the organic electroluminescent device may be enhanced, lifetime of the device may be improved, and an operating voltage of the device may also be reduced. To achieve the above-described technical objectives, the technical solutions of the present disclosure are as described below. The present disclosure provides a pyridine-fused carbene-based tetradentate cyclometalated platinum(II) complex. A structure of the pyridine-fused carbene-based tetradentate cyclometalated platinum(II) complex is as shown in formula (I): In formula (I), R1-R5 each independently represent from mono to maximum allowable substitution, or no substitution; R1-R5 are each independently selected from the group consisting of: hydrogen, deuterium (D), C1-C30 alkyl, C1-C30 deuterated alkyl, C6-C60 aryl, C6-C30 aryl silane, and combinations thereof; R is selected from the group consisting of hydrogen, deuterium, C1-C30 alkyl, C1-C30 cycloalkyl, C1-C30 deuterated alkyl, C6-C60 aryl, C6-C30 fused-ring aryl, and combinations thereof. Furthermore, R1-R5 are each independently selected from hydrogen, deuterium, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, n-hexyl, isohexyl, sec-hexyl, tert-hexyl, n-heptyl, isoheptyl, sec-heptyl, tert-heptyl, n-octyl, iso-octyl, sec-octyl, tert-octyl, n-nonyl, iso-nonyl, sec-nonyl, tert-nonyl, n-decyl, isodecyl, sec-decyl, tert-decyl, phenyl, triphenylsilane, and combinations thereof. Furthermore, R is selected from amantadine, tert-butyl, tert-butylphenyl, and groups represented by following structural formulas: R6 represents from mono to maximum substitution, or no substit