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 CsPbI 3 perovskite nanocrystals (PNCs), we introduced zero-dimensional perovskites Cs 4 PbI 6 for protection in addition to already robust SiO 2 all-inorganic encapsulation, via high-temperature solid-state synthesis. It is proven that the CsPbI 3 –Cs 4 PbI 6 nano-composite not only maintains the emission peak location of CsPbI 3 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 Cs 4 PbI 6. The passivation of defects on the interface of CsPbI 3 –Cs 4 PbI 6 contributes to the enhancement of photoluminescence quantum yield by 8%. These ultra stable CsPbI 3 –Cs 4 PbI 6 nano-composites show potentials in the application of luminous and display industries. • The CsPbI 3 –Cs 4 PbI 6 nano-composite is synthesized by high-temperature solid-state reaction method. • Samples have excellent thermal stability with the addition of ZnI 2. • Increased PLQY is corresponded to the passivation of defects on the interface. • Manifestation of carrier transitions between CsPbI 3 and Cs 4 PbI 6. [ABSTRACT FROM AUTHOR]