Synthesis of CsPbX3 lead halide perovskite nanocrystals in flower-like TiO2 matrices with enhanced stability

The instability of the cesium lead halide perovskite (CsPbX3, X = Cl, Br, I) upon exposure to humidity or heat strongly hinders their applications in optoelectronic devices. In this work, an in situ adsorption strategy is adopted to directly grow uniform CsPbX3 nanocrystals (NCs) on flower-like TiO2 microspheres to achieve a hybrid structure. Benefiting from the isolation effect of flower-like structure, the as-synthesized TiO2–CsPbBr3 composites exhibit excellent water stability when soaked in water for 35 days and retain 62.7% of the initial photoluminescence (PL) emission intensity. CsPbBr3 NCs also present enhanced thermal stability under the protection of TiO2 matrix. It is intriguing that the TiO2-CsPbX3 composites with blue, green and red emissions are fabricated successfully by this method with excellent moisture and thermal stability, which provides a feasible solution for the effective application of CsPbX3 NCs in light emitting diode (LED) devices.