biostudies-literatureUnknown9Wang LCompared to red and green organic light-emitting diodes (OLEDs), blue OLEDs are still the bottleneck due to the lack of efficient emitters with simultaneous high exciton utilization efficiency (EUE) and short excited-state lifetime. Different from the fluorescence, phosphorescence, thermally activated delayed fluorescence (TADF), and organic radical materials traditionally used in OLEDs, we demonstrate herein a new type of emitter, cerium(III) complex <b>Ce-1</b> with spin-allowed and parity-allowed <i>d</i>-<i>f</i> transition of the centre Ce³⁺ ion. The compound exhibits a high EUE up to 100% in OLEDs and a short excited-state lifetime of 42 ns, which is considerably faster than that achieved in efficient phosphorescence and TADF emitters. The optimized OLEDs show an average mLight, science & applications157https://www.ebi.ac.uk/biostudies/studies/S-EPMC7477100biostudies-literatureDeep-blue organic light-emitting diodes based on a doublet <i>d</i>-<i>f</i> transition cerium(III) complex with 100% exciton utilization efficiency.PMC7477100Yang HFang HDuan LHuang CLu ZZhao ZJiang NWang LLiu ZHuang TZhang YZhan GBian ZfalseDeep-blue organic light-emitting diodes based on a doublet <i>d</i>-<i>f</i> transition cerium(III) complex with 100% exciton utilization efficiency.Compared to red and green organic light-emitting diodes (OLEDs), blue OLEDs are still the bottleneck due to the lack of efficient emitters with simultaneous high exciton utilization efficiency (EUE) and short excited-state lifetime. Different from the fluorescence, phosphorescence, thermally activated delayed fluorescence (TADF), and organic radical materials traditionally used in OLEDs, we demonstrate herein a new type of emitter, cerium(III) complex <b>Ce-1</b> with spin-allowed and parity-allowed <i>d</i>-<i>f</i> transition of the centre Ce³⁺ ion. The compound exhibits a high EUE up to 100% in OLEDs and a short excited-state lifetime of 42 ns, which is considerably faster than that achieved in efficient phosphorescence and TADF emitters. The optimized OLEDs show an average m2020-01-01T00:00:00Z20202026-05-07T15:12:55.719Z2026-04-07T22:57:14.049ZS-EPMC74771003296376910.1038/s41377-020-00395-4