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

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 CsPbBr 3 QDs with lead phosphate (Pb 3 (PO 4 ) 2 ) shell through surface sacrificial coating (c-Ni-CsPbBr 3 ) have been developed based on a modified thermal injection approach. The synergistic effect of Ni doping and Pb 3 (PO 4 ) 2 coating effectively improves the stability and optical performances of CsPbBr 3 QDs, including photoluminescence (PL) intensity, the average lifetime, and PL quantum yield (QY). Thus, the c-Ni-CsPbBr 3 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-CsPbBr 3 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-CsPbBr 3 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.