Optimized encapsulation of CsPbBr3 nanocrystals in metal-organic framework by improved synthesis

Abstract

Instabilities of all inorganic perovskite nanocrystals (PeNCs) strictly limit their practical applications. Encapsulating PeNCs into metal-organic framework (MOF) has been recognized as an effective approach to improving the lifetime of PeNCs. However, the effects of various encapsulation methods on the performance and stabilities 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 probed, 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 lifetime, suppressed non-radiative recombination loss, enhanced photoluminescence quantum yield, 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 12-hour operation in ambient.