Harmonization of rapid triplet up-conversion and singlet radiation enables efficient and stable white OLEDs
Manli Huang, Zhanxiang Chen, Jingsheng Miao, siyuan he, Wei Yang, Zhongyan Huang, Yang Zou, Shaolong Gong, Yao Tan, Chuluo Yang
Abstract
White organic light-emitting diodes (WOLEDs) hold significant promise in illumination and displays, but achieving high efficiency while maintaining stability is an ongoing challenge. Here, we strategically combine a blue donor-acceptor thermally activated delayed fluorescence (TADF) emitter featuring rapid reverse intersystem crossing rate and a yellow multi-resonance TADF emitter renowned for the fast radiative transition process to achieve warm WOLEDs with exceptional power efficiency exceeding 190 lm W−1 and external quantum efficiency (EQE) of 39%, setting records for WOLEDs. Meanwhile, these devices also exhibit an extended operational lifetime (LT80) of 446 h at an initial luminance of 1000 cd m−2. Another group of blue and yellow emitters based on our strategy achieves a standard white emission and a high EQE of 35.6%, confirming the universality of our strategy. This work presents a versatile strategy to harmonize singlet exciton radiation and triplet exciton up-conversion, thus achieving a win-win situation of efficiency and stability. Achieving highly efficient and stable white organic light-emitting diodes remains challenging. Here, the authors report a strategy to harmonize singlet exciton radiation and triplet exciton up-conversion, attaining power and external quantum efficiency of 190 lm/W and 39% with an extended lifetime.