Luminescence and Stability Enhancement of CsPbBr₃ Perovskite Quantum Dots through Surface Sacrificial Coating

Abstract All‐inorganic perovskite quantum dots (QDs) have emerged as a new category of low‐cost semiconducting luminescent materials for optoelectronic applications. However, their poor stability has become the main challenge that impedes their potential applications. Herein, Ni‐doped CsPbBr₃ QDs with lead phosphate (Pb₃(PO₄)₂) shell through surface sacrificial coating (c‐Ni‐CsPbBr₃) have been developed based on a modified thermal injection approach. The synergistic effect of Ni doping and Pb₃(PO₄)₂ coating effectively improves the stability and optical performances of CsPbBr₃ QDs, including photoluminescence (PL) intensity, the average lifetime, and PL quantum yield (QY). Thus, the c‐Ni‐CsPbBr₃ QDs demonstrate the full width at half maxima (FWHM) and PLQY being 18.42 nm and 90.77%, respectively. The PL intensity of c‐Ni‐CsPbBr₃ can be maintained at 81% of its original value after being heated at 100 °C for 1 h. No phase transformation can be observed after being stored under ambient conditions (25 °C, 60% relative humidity (RH)) for 21 days. In addition, by combining green c‐Ni‐CsPbBr₃ QDs, red CdSe‐based QDs and the blue GaN chip, a QD enhancement film (QDEF) is fabricated to form a liquid crystal display (LCD) backlit with a wide color gamut covering cover 121% of the National Television System Committee (NTSC) standard.