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EP-4741408-A1 - TETRADENTATE CYCLOMETALATED PLATINUM (II) COMPLEX BASED ON PYRIDYLCARBAZOLE AND APPLICATION THEREOF, AND ELECTRONIC DEVICE

EP4741408A1EP 4741408 A1EP4741408 A1EP 4741408A1EP-4741408-A1

Abstract

The present invention belongs to the field of organic electroluminescence, and specifically relates to a tetradentate cyclometalated platinum (II) complex based on pyridylcarbazole and an application thereof, and an electronic device. In the present invention, a charge distribution in an excited state of a compound is improved by means of introducing a substituent group at an appropriate position of a ligand of the compound, such that there are more metal-to-pyridocarbene charge transfer states ( 3 MLCT) in an excited state of a material composed of the compound, which is conductive to improving a radiation rate, thereby extending the service life of a device. The material provided has good chemical stability and thermal stability, and is easily prepared into evaporated OLED devices. An organic electroluminescent device manufactured by using the compound of the present invention as a light-emitting layer has significantly improved current efficiency and service 1ife and a significantly reduced tum-on voltage. After the compound is combined with a fluorescent doped material (a boron-containing compound), transmissions of holes and electrons can be balanced, such that energy transfer between a host and a guest is more efficient, and the light color purity of a device can be improved.

Inventors

  • LI, GUIJIE
  • LU, Yunqi
  • ZHENG, JIANBING
  • SHE, YUANBIN
  • WU, KONGWU

Assignees

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

Dates

Publication Date
20260513
Application Date
20231204

Claims (13)

  1. A phenylpyridine-based tetradentate cyclometalated platinum (II) complex, characterized in that , the complex has a structure as shown in formula (I): wherein in formula (I), R 1 -R 6 each independently represent from mono to maximum allowable substitution, or no substitution; and R 1 -R 6 are each independently selected from the group consisting of: hydrogen, deuterium (D), halogen, C1-C30 alkyl, C1-C30 haloalkyl, substituted or unsubstituted C6-C60 aryl, and combinations thereof; and R a and R b are each independently selected from the group consisting of: hydrogen, deuterium, C1-C30 alkyl, substituted or unsubstituted C6-C60 aryl, and combinations thereof; and a substituent on each substituted C6-C60 aryl is deuterium, C1-C30 alkyl or C6-C60 aryl.
  2. The tetradentate cyclometalated platinum (II) complex according to claim 1, characterized in that , R a is selected from hydrogen, deuterium, CD 3 , C1-C10 alkyl, C6-C30 aryl, and combinations thereof; and R b is selected from hydrogen, deuterium, C1-C20 alkyl, and combinations thereof.
  3. The tetradentate cyclometalated platinum (II) complex according to claim 1, characterized in that , R 1 -R 6 are each independently selected from hydrogen, deuterium, CD 3 , F, CF 3 , methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl, heptyl, phenyl, and combinations thereof.
  4. The tetradentate cyclometalated platinum (II) complex according to claim 1, characterized in that , the tetradentate cyclometalated platinum (II) complex is any one selected from chemical structures shown below, wherein D represents deuterium:
  5. An application of the tetradentate cyclometalated platinum(II) complex according to any one of claims 1 to 4 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.
  6. 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 4.
  7. 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 4.
  8. The organic electroluminescent device according to claim 7, characterized in that , the light-emitting layer further contains a fluorescent dopant material.
  9. 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 4.
  10. The organic optoelectronic device according to claim 9, characterized in that , the organic light-emitting functional layer further contains a fluorescent dopant material.
  11. A composition, characterized in that , the composition contains the tetradentate platinum(II) complex according to any one of claims 1 to 4.
  12. A formulation, characterized in that , the formulation contains the tetradentate platinum(II) complex according to any one of claims 1 to 4.
  13. A display or lighting apparatus, characterized in that , the apparatus comprises at least one organic electroluminescent device each according to any one of claims 6 to 8.

Description

TECHNICAL FIELD The present disclosure relates to the field of organic electroluminescence, specifically to a tetradentate cyclometalated platinum(II) complex based on pyridyl-carbazole, an electronic device, and an application thereof. BACKGROUND Organic light-emitting diodes (OLEDs) represent a new generation of full-color display and lighting technology. Compared to the liquid crystal display which suffers from slow response, narrow viewing angle, need for backlight and high energy consumption, OLEDs as self-luminous devices offer advantages such as no requirement for backlight, high energy efficiency, 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 addition, OLEDs further offer advantages such as low production cost, simple manufacturing process and suitability for large-format products. Therefore, OLEDs possess broad and significant application prospects in high-end electronic products and the aerospace fields. With a gradual increase in investment, further in-depth research and development and upgrading of production equipment, OLEDs will have extensive application scenarios and promising development potential in the future. The core of the development of OLEDs lies in design and development of light-emitting materials. At present, light-emitting layers of OLED devices in use 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 (Pd) (II). Commonly used phosphorescent organic materials 3,3'-bis(9-carbazolyl)-biphenyl (i.e., mCBP) and 2,6-bis(9-carbazolyl)-pyridine (i.e., 2,6-mCPy) possess high efficiency and high triplet energy levels, and when the materials are used as organic materials, triplet energy can be effectively transferred from the light-emitting organic materials to guest phosphorescent materials. However, mCBP exhibits high hole mobility but poor electron transport capability, and 2,6-mCPy suffers from inadequate hole transport. This causes charges in the light-emitting layers to be unbalanced, resulting in a decrease in current efficiency of devices. Moreover, heavy-metal phosphorescent organic complexes in use are mainly cyclometalated iridium(III) complex molecules, whose variety is limited. The abundance of platinum in the Earth's crust and the annual global production of platinum are both approximately ten times greater than those of iridium; and the price of IrCl3·H2O used for preparing iridium(III) complex phosphorescent materials is significantly higher than that of PtCl2 used for preparing platinum(II) complex phosphorescent materials. Additionally, the preparation of the iridium(III) phosphorescent materials involves four steps: preparation of an iridium(III) dimer, ligand exchange of an iridium (III) intermediate, synthesis of a mer-iridium(III) complex, and isomerization from mer- to fac-iridium(III) complex. This substantially reduces an overall yield, greatly decreases utilization ratio of a starting material IrCl3·H2O, and consequently increases a production cost of the iridium(III) phosphorescent materials. In contrast, the preparation of the platinum(II) complex phosphorescent materials consists of just one step: ligand metallation. This process affords a high utilization ratio of platinum, thereby further reducing a production cost of the platinum(II) complex phosphorescent materials. In summary, the production cost of the platinum (II) complex phosphorescent materials is much lower than that of the iridium (III) complex phosphorescent materials. However, there are still some technical challenges in the development of the 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 tetradentate cyclometalated platinum(II) complex based on pyridyl-carbazole, an electronic device, and an application thereof. When used as a guest phosphorescent material of a light-emitting layer, the tetradentate cyclometalated platinum(II) complex based on pyridyl-carbazole in the present disclosure may enable a device to exhibit excellent performance, current efficiency of an organic electroluminescent device may be enhanced, lifetime of the device may be improved, and an operating voltage of the device may also be reduced.