Highly efficient white light-emitting diodes with a bi-component emitting layer based on blue and yellow thermally activated delayed fluorescence emitters

Herein, highly efficient white light-emitting diodes with a bi-component light emitting layer of the blue TADF emitter 2'-(dimesitylboranyl)-N,N-diphenyl-[ 1,1'-biphenyl]-2-amine (o,o'-NPh2) and the yellow TADF emitter 4-phenyl-4'-carbazole-9-H-thioxanthen-9-one-10,10-dioxide (TXO-PhCz4) is reported, providing white light emission with a CIE of (0.38, 0.40), a high CRI of 71, and a maximum EQE of 12.5%, which is among the best of WOLEDs with a bi-component emitting layer.