Highly Luminescent Transparent Cs2AgxNa1-xBiyIn1-yCl6 Perovskite Films Produced by Single-Source Vacuum Deposition

Thermal deposition of halide perovskites as a universal and scalable route to transparent thin films becomes highly challenging in the case of lead-free double perovskites, requiring the evaporation dynamics of multiple metal halide sources to be balanced or a single-phase precursor preliminary synthesized to achieve a reliable control over the composition and the phase of the final films. In the present Letter, the feasibility of the single-source vacuum deposition of microcrystalline Cs2AgxNa1-xBiyIn1-yCl6 double perovskites into corresponding transparent nanocrystalline films while preserving the bulk spectral and structural properties is shown. The perovskite films produced from the most emissive powders with x = 0.40 and y = 0.01 revealed a photoluminescence quantum yield of 85%, highlighting thermal evaporation as a promising approach to functional perovskite-based optical materials.

Automated summary

The thermal deposition of lead-free double perovskites for transparent thin films is challenging due to the need to balance the evaporation dynamics of multiple metal halide sources or synthesize a single-phase precursor. This study demonstrates the feasibility of single-source vacuum deposition to produce transparent nanocrystalline films of microcrystalline Cs2AgxNa1-xBiyIn1-yCl6 double perovskites while maintaining their bulk spectral and structural properties. The perovskite films derived from the most emissive powders exhibited a photoluminescence quantum yield of 85%, indicating the promising use of thermal evaporation for perovskite-based optical materials.