Mono‐Component Pure‐White Light‐Emitting Diodes Based on Eco‐Friendly ZnCuGaS:In@ZnS Quantum Dots with Near‐Unity Quantum Yield and Balanced Red‐Green‐Blue Centers

Abstract White light‐emitting diodes (WLEDs) are the key components in the next‐generation lighting and display devices. The inherent toxicity of Cd/Pb‐based quantum dots (QDs) limits the further application in WLEDs. Recently, more attention is focused on eco‐friendly QDs and their WLEDs, especially the phosphor‐free WLEDs based on mono‐component, which profits from bias‐insensitive color stability. However, the imbalanced carrier distribution between red‐green‐blue luminescent centers, even the absence of a certain luminescent center, hinders their balanced and stable photoluminescence/electroluminescence (PL/EL). Here, an In 3+ ‐doped strategy in Zn‐Cu‐Ga‐S@ZnS QDs is first proposed, and the balanced carrier distribution is realized by non‐equivalent substitution and In 3+ doping concentration modulation. The alleviation of the green emitter by the In 3+ ‐related red emitter and the compensation of blue emitter by the Zn‐related electronic states contribute to the balanced red‐green‐blue emitting with high PL quantum yield (PLQY) of 95.3% and long lifetime (T 90 ) of over 1100 h in atmospheric conditions. Thus, the In 3+ ‐doped WLEDs can achieve exceedingly slight proportional variations between red‐green‐blue EL intensity over time (∆CIE = (0.007, 0.009)), and high champion CRI of 94.9. This study proposes a single‐component QD with balanced and stable red‐green‐blue PL/EL spectrum, meeting the requirements of lighting and display.