A Novel Matrix-Free Hyperfluorescent System Based on Anti-Quenching TADF Host for High Color Purity MR-TADF Emitters

Organic light-emitting diodes (OLEDs) based on hyperfluorescent system have attracted widespread attention due to their ability to simultaneously achieve improvements in efficiency, lifetime, and color purity by combining the advantages of high exciton utilization sensitizers and high-color purity emitters. Traditional hyperfluorescent systems typically involve three or four components and are severely sensitive to the doping concentration (≈0.5 wt%) of a terminal emitter, which inevitably causes high costs and difficulties in reproducibility. Here, a novel design concept for a matrix-free hyperfluorescent (MFHF) system that employs a combination of an anti-quenching TADF host and a high color purity MR-TADF emitter is proposed. This strategy allows traditional concentration-sensitive MR-TADF emitters to significantly improve exciton utilization and reduce exciton lifetime at high doping levels, without the need for complex molecular modifications. The OLEDs with binary emissive layer achieve pure-green emission, a maximum external quantum efficiency of over 30%, and a high maximum power efficiency of 145 lm W^-1. The approach offers a straightforward and universal method to achieve anti-quenching matrix-free hyperfluorescent OLEDs with high color purity, making them promising for commercial applications in low-cost ultra-high-definition (UHD) displays.