Optimized encapsulation of CsPbBr3 nanocrystals in metal–organic frameworks by improved synthesis

Abstract

Instabilities of all-inorganic perovskite nanocrystals (PeNCs) strictly limit their practical applications. Encapsulating PeNCs into metal–organic frameworks (MOFs) has been recognized as an effective approach to improving the lifetime of PeNCs. However, the effects of various encapsulation methods on the performance and stability of PeNCs@MOF composites remain ambiguous. Herein, all-inorganic CsPbBr₃ NCs were encapsulated into a screened MOF, i.e., MIL-53 (Al), via one-step and two-step synthesis methods. Distinct morphologies and NC distribution in MOFs were investigated, which might be ascribed to different chemical environments and interactions between CsPbBr₃ NCs and MOFs in the two methods. As a result, the two-step CsPbBr₃@MOF composites demonstrated increased charge carrier lifetimes, suppressed non-radiative recombination loss, enhanced photoluminescence quantum yields, as well as increased hydrophobicity compared to pristine CsPbBr₃ NCs and one-step samples. Moreover, the CsPbBr₃@MOF-based white light emitting diode retained over 90% performance after a 12-hour operation under ambient conditions.