Ultrafast dual-pathway room-temperature synthesis of 0D inorganic metal halides K3SbCl6 with near-unity photoluminescence quantum yield
Alkali metal halides such as KCl are typical insulators with broad bandgaps, exhibiting poor luminescence. Ion doping can enhance their luminescence, but the mechanism of ultrafast diffusion and structural evolution remains unclear. Here, Sb3+ was doped into a KCl matrix via a room-temperature grinding route. Varying Sb3+ concentration induces a structural evolution from KCl:Sb3+ to 0D inorganic metal halides (IMHs) K3SbCl6. The resulting K3SbCl6 exhibits broad-spectrum yellow emission with near-unity photoluminescence quantum yield (PLQY). The luminescence mechanism is attributed to the 3P1→1S0 transition of Sb3+ ions. Furthermore, a room-temperature solid-liquid interface diffusion method enables ultrafast single-crystal growth of K3SbCl6 in only 20 seconds, with stable luminescence. The material demonstrates excellent temperature sensing performance in the 50–310 K range, achieving a maximum relative sensitivity of 9.99%/K. Additionally, K3SbCl6 shows application potential in information encryption, flexible composite fluorescent films, and white light-emitting diodes. This study provides new insights into ultrafast synthesis of high-performance luminescent materials.