Direct photoinduced synthesis of lead halide perovskite nanocrystals and nanocomposites.

• A unique photoinduced method is developed for the controlled synthesis of CsPbX 3 PeNCs. • The synthesis is dictated by the light-triggered breakage of the covalent C-X bond of haloalkanes. • The method enables in situ confined growth of CsPbX 3 PeNCs in mSiO 2 at a single particle level. • Uniform UCNPs@mSiO 2 @CsPbX 3 core/shell nanostructures are achieved based on the photoinduced synthesis. • The photoinduced method breaks through the limitations of conventional methods for synthesizing CsPbX 3 PeNCs. [Display omitted] All-inorganic CsPbX 3 (X = Cl, Br, and I) perovskite nanocrystals (PeNCs) and nanocomposites have shown great promise in optoelectronics and photovoltaics. However, it remains notoriously difficult to control over perovskite nanocomposites at a single particle level. Herein, we report a unique photoinduced method for the controlled synthesis of CsPbX 3 PeNCs and nanocomposites based on the light-triggered breakage of the covalent carbon-halogen bond of haloalkanes. The use of molecular haloalkanes as unreactive halide source provides a mild reaction condition, which enables in situ confined growth of CsPbX 3 PeNCs in mesoporous nanospheres such as silica with well-defined morphology. As a result, a variety of multifunctional perovskite nanocomposites can be achieved through photoinduced confined growth of PeNCs in mesoporous silica coated nanoparticles. These findings provide a general approach for synthesizing CsPbX 3 PeNCs and nanocomposites, which may open up new opportunities for perovskite-based material or device engineering towards versatile applications. [ABSTRACT FROM AUTHOR]