Manipulating Exciton Dynamics toward Simultaneous High-Efficiency Narrowband Electroluminescence and Photon Upconversion by a Selenium-Incorporated Multiresonance Delayed Fluorescence Emitter

Xiaosong Cao; Ke Pan; Jingsheng Miao; Xialei Lv; Zhongyan Huang; Fan Ni; Xiaojun Yin; Yaxiong Wei; Chuluo Yang

doi:10.1021/jacs.2c09543

Manipulating Exciton Dynamics toward Simultaneous High-Efficiency Narrowband Electroluminescence and Photon Upconversion by a Selenium-Incorporated Multiresonance Delayed Fluorescence Emitter

J Am Chem Soc. 2022 Dec 21;144(50):22976-22984. doi: 10.1021/jacs.2c09543. Epub 2022 Dec 7.

Authors

Xiaosong Cao¹, Ke Pan¹, Jingsheng Miao¹, Xialei Lv¹, Zhongyan Huang¹, Fan Ni¹, Xiaojun Yin¹, Yaxiong Wei², Chuluo Yang¹

Affiliations

¹ Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen518060, China.
² Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, School of Physics and Electronic Information, Anhui Normal University, Wuhu241000, China.

PMID: 36475679
DOI: 10.1021/jacs.2c09543

Abstract

Multiresonance thermal activated delayed fluorescence (MR-TADF) materials with an efficient spin-flip transition between singlet and triplet excited states remain demanding. Herein, we report an MR-TADF compound (BN-Se) simultaneously possessing efficient (reverse) intersystem crossing (ISC/RISC), fast radiative decay, close-to-unity quantum yield, and narrowband emission by embedding a single selenium atom into a common 4,4'-diazaborin framework. Benefitting from the high RISC efficiency accelerated by the heavy-atom effect, organic light-emitting diodes (OLEDs) based on BN-Se manifest excellent performance with an external quantum efficiency of up to 32.6% and an ultralow efficiency roll-off of 1.3% at 1000 cd m^-2. Furthermore, the high ISC efficiency and small inherent energy loss also render BN-Se a superior photosensitizer to realize the first example of visible (λ_ex > 450 nm)-to-UV (λ_em < 350 nm) triplet-triplet annihilation upconversion, with a high efficiency (21.4%) and an extremely low threshold intensity (1.3 mW cm^-2). This work not only aids in designing advanced pure organic molecules with fast exciton dynamics but also highlights the value of MR-TADF compounds beyond OLED applications.