Solid-Phase Grinding Synthesis of Lead-Free Cs2Ag1-xNaxIn1-yBiyCl6 Nanocrystals for Efficient Light Emission

In recent years, the lead-free halide perovskite has been extensively studied due to the the lead toxicity and poor stability of lead halide perovskite. Cs2AgInCl6 has shown great potential to replace lead halide perovskites in optoelectronic applications. However, this perovskite synthesis method needs to involve high temperature, the synthesis conditions are relatively harsh. In this work, a simple solid-phase grinding method was employed to prepare Na+ and Bi3+ doped perovskite Cs2Ag1-xNaxIn1-yBiyCl6 with systematically characterization of both the structure and optical performance. The experimental results showed that a photoluminescence quantum yield (PLQY) of 13.1% was achieved by breaking the parity-forbidden transition through 4% Bi³⁺ doping. Subsequently, the incorporation of 60% Na⁺ suppressed non-radiative transitions and increased the PLQY to 56.9%. The Cs2Ag0.4Na0.6In0.96Bi0.04Cl6 samples were encapsulated on ultraviolet (UV) LED chips to obtain warm-yellow LED with good performances, which shows that promising applications in the LED field.