High temperature solid reaction synthesis of ultra-stable CsPbI₃–Cs₄PbI₆ nano-composites sealed in SiO₂ particles

Rigid protection layers for the lead-halide perovskite effectively enhance its stability. In this work, for the most vulnerable CsPbI₃ perovskite nanocrystals (PNCs), we introduced zero-dimensional perovskites Cs₄PbI₆ for protection in addition to already robust SiO₂ all-inorganic encapsulation, via high-temperature solid-state synthesis. It is proven that the CsPbI₃–Cs₄PbI₆ nano-composite not only maintains the emission peak location of CsPbI₃ PeNCs at 700 nm with remarkable oxygen and water resistances, but also exhibits enhanced instant and long-term thermal stability compared with samples containing less amount of Cs₄PbI₆. The passivation of defects on the interface of CsPbI₃–Cs₄PbI₆ contributes to the enhancement of photoluminescence quantum yield by 8%. These ultra stable CsPbI₃–Cs₄PbI₆ nano-composites show potentials in the application of luminous and display industries.