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 (kRISC) of 2.0 × 106 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.
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This work was funded by the National Natural Science Foundation of China (grant no. 52130308 to C.Y.), the Shenzhen Science and Technology Program (grant nos. KQTD20170330110107046 and ZDSYS20210623091813040 to C.Y.) and the China Postdoctoral Science Foundation (grant no. 2021M692183 to Y.X.H.). We thank C. Zhong (Department of Chemistry, Wuhan University) for the assistance with theoretical calculations, as well as Y. Gu and X. Zhou (TCL China Star Optoelectronics Technology) for their assistance with the optical simulation of the devices. We also thank the Instrumental Analysis Center of Shenzhen University for analytical support.
SZU has filed patent applications on materials and devices. C.Y., Y.X.H. and J.M. are the authors of the invention. CN patent application no. 2021113469101 (pending). The other authors declare no competing interests.
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Hu, Y.X., Miao, J., Hua, T. et al. Efficient selenium-integrated TADF OLEDs with reduced roll-off. Nat. Photon. 16, 803–810 (2022). https://doi.org/10.1038/s41566-022-01083-y
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