Efficient selenium-integrated TADF OLEDs with reduced roll-off

• Published in: Nature photonics Vol. 16; no. 11; pp. 803 - 810
• Main Authors: Hu, Yu Xuan, Miao, Jingsheng, Hua, Tao, Huang, Zhongyan, Qi, Yanyu, Zou, Yang, Qiu, Yuntao, Xia, Han, Liu, He, Cao, Xiaosong, Yang, Chuluo
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.11.2022; Nature Publishing Group
• Subjects: 140/131; 639/301/1019/1020/1091; 639/624/1020/1091; Applied and Technical Physics; Boron; Efficiency; Emitters; Excitons; Fluorescence; Narrowband; Organic light emitting diodes; Photoluminescence; Photons; Physics; Physics and Astronomy; Power efficiency; Quantum efficiency; Quantum Physics; Selenium
• ISSN: 1749-4885; 1749-4893
• DOI: 10.1038/s41566-022-01083-y

Organic light emitters based on multiresonance-induced thermally activated delayed fluorescent materials have great potential for realizing efficient, narrowband organic light-emitting diodes (OLEDs). However, at high brightness operation, efficiency roll-off attributed to the slow reverse intersystem crossing (RISC) process hinders the use of multiresonance-induced thermally activated delayed fluorescent materials in practical applications. Here we report a heavy-atom incorporating emitter, BNSeSe, which is based on a selenium-integrated boron–nitrogen skeleton and exhibits 100% photoluminescence quantum yield and a high RISC rate ( k RISC ) of 2.0 × 10 6  s −1 . The corresponding green OLEDs exhibit excellent external quantum efficiencies of up to 36.8% and ultra-low roll-off character at high brightnesses (with very small roll-off values of 2.8% and 14.9% at 1,000 cd m −2 and 10,000 cd m −2 , respectively). Furthermore, the outstanding capability to harvest triplet excitons also enables BNSeSe to be a superior sensitizer for a hyperfluorescence OLED, which shows state-of-the-art performance with a high excellent external quantum efficiency of 40.5%, power efficiency beyond 200 lm W −1 , and luminance close to 20,0000 cd m −2 . Green OLEDs based on BNSeSe offer high operational efficiency and reduced efficiency roll-off.