Highly efficient luminescence and enhanced stability of nanocomposites by encapsulating perovskite quantum dots in defect-related luminescent silica nanospheres

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The metal-halide perovskite quantum dots (PQDs) have been emerged as new stars of optoelectronic materials with fascinating luminescence properties. However, the poor stability of these materials severely restricts their practical applications. In this work, the novel defect-related luminescent mesoporous silica nanospheres are employed as protective matrix to improve the stability of PQDs for the first time. Firstly, the monodisperse CsPbBr3 and CsPbBr1.5I1.5 PQDs with perfect nanocube morphology and eminent luminescence properties have been prepared respectively by a facile synthesis strategy. Then, the CsPbBr3 and CsPbBr1.5I1.5 PQDs are encapsulated into the non-luminescent (SN) and luminescent silica matrix (DL-SN) respectively, resulting in the PQDs@SN and PQDs@DL-SN nanocomposites. The incorporation of the PQDs and silica matrix can be confirmed by XRD, FT-IR, TEM, XPS, elemental mapping images, N2 adsorption/desorption isotherms, and density functional theory. The as-synthesized silica matrix especially for the DL-SN presents a remarkable enhancement of stability against temperature, storage time, and water for both CsPbBr3 and CsPbBr1.5I1.5 in comparison to the pristine PQDs. Furthermore, the formation mechanism and stability improvement mechanism have been discussed in detail. This work provides a facile and general approach to solve the intrinsic instability of all-inorganic PQDs, which may have a significant impact on their practical applications.