High-quality and stable perovskite nanocrystals with enhanced properties via photo-brightening

Colloidal inorganic perovskite CsPbX₃ nanocrystals (NCs) with extraordinary properties have emerged as key materials for light management in next-generation optoelectronic devices. Cyan-emitting perovskites show strong potential for high-quality lighting applications. In terms of post-treatment, light irradiation can cause considerable changes in optical features, leading to either photo-brightening or photo-darkening effects. Here, we report a facile strategy and detailed protocols for the synthesis of high-quality, stable Cs–Pb–Br NCs that emit green–blue light by systematically varying the PbBr₂ ratios. The proposed strategy enables the reproducible preparation of Cs–Pb–Br NCs with narrow size distributions. In addition, photo-brightening in high-quality and stable Cs–Pb–Br perovskite NCs enhanced the photoluminescence (PL) properties. Under laser irradiation, the cyan-emitting Cs–Pb–Br NCs with a Cs:Pb molar ratio of 1:10.4 exhibited a ∼40 % increase in PL intensity, attributed to the repair of Br vacancies by O₂ adsorption.