Hypsochromic Shift of Multiple-Resonance-Induced Thermally Activated Delayed Fluorescence by Oxygen Atom Incorporation

Herein, we reported an ultrapure blue multiple-resonance-induced thermally activated delayed fluorescence (MR-TADF) material (nu-DABNA-O-Me) with a high photoluminescence quantum yield and a large rate constant for reverse intersystem crossing. Because of restricted pi-conjugation of the HOMO rather than the LUMO induced by oxygen atom incorporation, nu-DABNA-O-Me shows a hypsochromic shift compared to the parent MR-TADF material (nu-DABNA). An organic light-emitting diode based on this material exhibits an emission at 465 nm, with a small full-width at half-maximum of 23 nm and Commission Internationale de l'Eclairage coordinates of (0.13, 0.10), and a high maximum external quantum efficiency of 29.5 %. Moreover, nu-DABNA-O-Me facilitates a drastically improved efficiency roll-off and a device lifetime compared to nu-DABNA, which demonstrates significant potential of the oxygen atom incorporation strategy.

Automated summary

This study reported an ultrapure blue fluorescent material (nu-DABNA-O-Me) with high photoluminescence quantum yield and a large rate constant for reverse intersystem crossing. An organic light-emitting diode based on this material exhibited excellent performance, demonstrating the significant potential of the oxygen atom incorporation strategy.