A gold(iii)-TADF emitter as a sensitizer for high-color-purity and efficient deep-blue solution-processed OLEDs

Abstract

Herein is described a blue-emitting gold(iii)-TADF complex Au-1 that could act as a sensitizer for a solution-processed organic light-emitting diode (SP-OLED), in which a multi-resonance TADF emitter ν-DABNA is employed as the emissive dopant. Photophysical investigations revealed an efficient energy transfer (ET) process in the sensitized system with estimated Förster distance of 2.83 nm and ET rate of 2.35 × 107 s−1. The fabricated blue SP-OLEDs attained high maximum external quantum efficiency of up to 16.6%, high color purity with a full-width at half maximum of 23 nm and Commission Internationale de L’Éclairage coordinates of (0.14, 0.18). A slight efficiency roll-off of 13% was observed for the Au-1 sensitized ν-DABNA-based device, which is much improved relative to that (30%) of the Au-1-based device, attributed to the effective ET process from Au-1 to ν-DABNA that could suppress the accumulation of triplet excitons on Au-1 at high luminance.