High-temperature evolution processes of exciplex states in the TBRb/C60 planar-heterojunction OLEDs via in-situ heating

IF 6.8 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Science China Materials Pub Date : 2025-01-02 DOI:10.1007/s40843-024-3192-3

Hongqiang Zhu (, ), Kaihui Yin (, ), Zebang Wu (, ), Lei Luo (, ), Weiyao Jia (, ), Xi Zhao (, ), Jing Chen (, ), Song Yang (, ), Yingfei Yi (, ), Yun Liu (, ), Zuhong Xiong (, )

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引用次数: 0

Abstract

Magneto-conductance (MC) was used as a fingerprint detection tool to contactlessly visualize high-temperature evolution processes of exciplex (EX) states in the TBRb/C₆₀ planar-heterojunction (PHJ) organic light-emitting diodes (OLEDs). Specifically, MC was used to contactlessly observe at room temperature around 300 K. The reverse intersystem crossing (RISC) process from triplet to singlet EX states (EX₃→ EX₁) in the device at 300 K is observed for the first time from the TBRb/C₆₀ PHJ-OLED. The device shows a half-band-gap turn-on photoelectric characteristics. Temperature-dependent MC traces of the device present an interesting conversion from RISC to triplet-charge annihilation (TQA) process between EX₃ and charge carriers (T₁ + q → e + h + q′) after the device temperature increasing from 300 to 425 K via in-situ heating. By comprehensively analyzing MC traces, current-voltage characteristic curves, transient electroluminescence spectra, and optical microscopy images of the device and atomic force microscopy images of the TBRb film, we find that the increase of temperature destroys the molecule structures of organic materials, which leads to the generation of many traps inside the organic semiconductor films comprising the TBRb/C₆₀ PHJ-OLED. These traps will capture polaron-pairs, EX, and exciton states and then affect their interactions, which finally induces the changes of MC traces. This work not only deepens understandings of high-temperature evolution processes of polaron-pairs, EX, and exciton states in the TBRb/C₆₀ PHJ devices, but also provides a new method to study the microscopic mechanisms in OLED operating in high temperature environment.

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来源期刊

Science China Materials Materials Science-General Materials Science

CiteScore

11.40

自引率

7.40%

发文量

949

期刊介绍： Science China Materials (SCM) is a globally peer-reviewed journal that covers all facets of materials science. It is supervised by the Chinese Academy of Sciences and co-sponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China. The journal is jointly published monthly in both printed and electronic forms by Science China Press and Springer. The aim of SCM is to encourage communication of high-quality, innovative research results at the cutting-edge interface of materials science with chemistry, physics, biology, and engineering. It focuses on breakthroughs from around the world and aims to become a world-leading academic journal for materials science.