Two-Step Hybrid Passivation Strategy for Ultrastable Photoluminescence Perovskite Nanocrystals

Perovskite nanocrystals (NCs) are promising light-emitting materials for next-generation illuminations and displays. The main challenge for practical applications is to achieve high durability. Herein, a hybrid passivation strategy was developed to simultaneously enhance the photoluminescence quantum yield (PLQY) and the stability of perovskite CsPbBr3 NCs by two-step modification with surface halogen replenishment and atomic layer deposition. The hybrid passivation mechanisms regarding the repairing of NCs’ surface Pb–Br octahedron as well as insertion of inorganic AlOx on the NCs’ surface were unraveled. The obtained CsPbBr3 NC films not only have high PLQY but also retain 100% of original PL value after UV illumination for 48 h, which was quantitatively assessed as the most stable solid-state CsPbBr3 NC film ever reported. Based on the passivation method, a high-lumen white light-emitting diode (LED) device exhibiting working durability was successfully fabricated. This strategy is beneficial for fabricating ultrastable perovskite phosphors and significantly improving their potential in LED illumination and backlight displays.