Article by Dr Marcin Lindner in Angewandte Chemie International Edition

29 March 2022

Although bowl-shaped N-pyrrolic polycyclic aromatic hydrocarbons (PAHs) can achieve excellent electron-donating ability, their application for optoelectronics is hampered by typically low photoluminescence quantum yields (PLQYs). To address this issue, we report the synthesis and characterization of a series of curved and fully conjugated nitrogen-doped PAHs. Through structural modifications to the electron-accepting moiety, we are able to switch the mechanism of luminescence between TADF and RTP, and to tune the overall PLQY in the range from 9% to 86%. As a proof of concept, we constructed solid-state OLED devices which has not been explored so far in the context of concave N-doped systems being TADF/RTP emitters. The best-performing dye, possessing peripheral trifluoromethyl group adjacent to phenazine acceptor, exhibits yellow to orange emission with a maximum external EL quantum efficiency (EQE) of 12%, which is the highest EQE in an curved D-A embedded N-PAH to date.


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