Highly luminescent CsPbX3@MIL-53(Al) nanoarchitectonics with anomalous stability towards flexible emitting films

Abstract

The poor stability of perovskite nanomaterials exposed in high temperature, moisture, light radiation, and polar solvent conditions severely restrict their commercial application. To address this issue, the growth in situ of CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) is carried out by using the stable aluminum (Al)-based metal-organic frameworks to create CsPbX3@MIL-53(Al) composites. Compared with pristine CsPbX3 NCs prepared using room temperature ligand assisted re-precipitation synthesis, the CsPbX3@MIL-53(Al) composites exhibit narrow photoluminescence (PL) spectra and greatly improved stability. The green emitting CsPbBr3@MIL-53(Al) composite exhibit narrowed PL spectrum (the full width at half-maximum of PL spectra: 20 nm for the composite and 28 nm for CsPbBr3 NCs) and a blue-shifted PL peak wavelength (517.6 nm for the composite and 527.6 nm for the CsPbBr3 NCs). The relationship of microstructure, components, PL, fluorescence lifetime, and stability are discussed systematically. Anomalous stability against heat-treatment, polar solvent and humidity conditions indicated the composites retained their initial PL intensity after storge more than 4 months in ambient conditions and heat-treated to 120ºC for 5 cycles. The emitting color of CsPbBr3@MIL-53(Al) composites are easily adjusted from blue, green to red by controlling the halide components of precursors. The composite was used to create emitting coating and highly bright flexible emitting films which also reveal high stability, suggesting that in situ encapsulation of CsPbX3 NCs in MIL-53(Al) would supply a novel platform for various emitting devices.