 The authors combined multiple resonance effect and multilock 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 luminescence of half a million nits. This article was authored by Jun Yuan Liu, Yun Huishu, Tai Chi Suboi, and others.