Robust Luminescent Molecules with High-Level Reverse Intersystem Crossing for Efficient Near Ultraviolet Organic Light-Emitting Diodes

作者：Chen, Jinke; Liu, Hao; Guo, Jingjing; Wang, Jianghui; Qiu, Nuoling; Xiao, Shu; Chi, Jiajin; Yang, Dezhi; Ma, Dongge; Zhao, Zujin^*; Tang, Ben Zhong

来源：Angewandte Chemie - International Edition, 2022, 61(10): e202116810.

DOI：10.1002/anie.202116810

• Forster Energy Transfer
• Magneto-Electroluminescence
• Near Ultraviolet Light
• Organic Light-Emitting Diodes
• Reverse Intersystem Crossing

Organic light-emitting diodes (OLEDs) radiating near ultraviolet (NUV) light are of high importance but rarely reported due to the lack of robust organic short-wavelength emitters. Here, we report a short pi-conjugated molecule (POPCN-2CP) with high thermal and morphological stabilities and strong NUV photoluminescence. Its neat film exhibits an electroluminescence (EL) peak at 404 nm with a maximum external quantum efficiency (eta(ext,max)) of 7.5 % and small efficiency roll-off. The doped films of POPCN-2CP in both non-polar and polar hosts at a wide doping concentration range (10-80 wt%) achieve high-purity NUV light (388-404 nm) and excellent eta(ext,max)s of up to 8.2 %. The high-level reverse intersystem crossing improves exciton utilization and accounts for the superb eta(ext,max)s. POPCN-2CP can also serve as an efficient host for blue fluorescence, thermally activated delayed fluorescence and phosphorescence emitters, providing excellent EL performance via Forster energy transfer.