 The authors combined multiple resonance effect and multi-lock strategy to dope green emitting thermally activated delayed fluorescent molecules into green emitting phosphorescence OLEDs by endowing the device with a broadcast service television 2020 colour gamut, 50% improved EQE, and a high human essence of half a million nits. This article was authored by Jun Yuan Liu, Yun Huizhou, Taiju Suboy, and others.