CsPbBr 3 /Cu, Mn‐Doped ZnInS Quantum Dot Composites for Full‐Spectrum WLEDs With High Color Rendering and External Quantum Efficiency

ABSTRACT Quantum dots (QDs) stand out as promising luminescent materials for next‐generation white light‐emitting diodes (WLEDs) owing to their outstanding optical properties and facile solution processability. Unfortunately, current QD‐based WLEDs are still plagued by low color rendering index (CRI) and external quantum efficiency (EQE). Herein, a “cascaded energy transfer” strategy is introduced to achieve full‐spectrum white light emission, by constructing a novel CsPbBr 3 /Cu,Mn‐doped ZnInS QD composite. Femtosecond transient absorption measurements verify that the designed system undergoes dual‐path energy transfer via Förster resonance energy transfer and Dexter‐type energy transfer mechanisms. The resulting full‐spectrum WLED delivers a CRI of 92.6 and an EQE of 7.5%, presenting the optimal balanced performance among documented QD‐based devices. This strategy paves a promising way for developing high‐efficiency and high‐color‐rendering QD‐based lighting devices.