Stable and highly luminescent CsPbX3 (X= Br, Br/Cl) perovskite quantum dot embedded into Zinc(II) imidazole-4,5-dicarboxylate metal organic framework as a luminescent probe for metal ion detection

All inorganic lead halide perovskite nanocrystals (PeNCs) also called quantum dots (QDs) have emerged as a unique class of luminescent materials suitable for lighting and display technology. Unfortunately, such QDs are prone to degradation in ambient conditions, which inhibits their practical applicability. In this approach, CsPbX3 (X = Br, Br/Cl) PeNC was synthesized via a facile surfactant free two step in-situ growth technique by confining PeNC into the pores of a Zn based metal organic framework (MOF). The MOF was synthesized using zinc nitrate as a metal source and 4, 5-imidazole di-carboxylic acid as a linker. The formation of the PeNC/MOF composite was confirmed by XRD, SEM, TEM, and XPS analysis. Energy transfer from the Zn-HIMDC MOF matrix to the CsPbBr3 PeNC has been detected which in turn enhances its optical properties. The resulting CsPbBr3@MOF composite showed a very narrow and intense emission with full width half maxima (FWHM) at 20.5 nm. The emission maxima of CsPbX3@MOF was blue shifted with the addition of smaller halide Cl−. Due to the incorporation into the MOF template, the PeNC/MOF composite exhibits remarkable stability against moisture, ultraviolet light, heat, and polar solvents. Further, its superior stability and processibility have been exemplified by using it as a fluorescent probe for metal ion sensing.