A green and general room-temperature synthesis of doped 0D perovskites for tunable and enhanced luminescence

Zero-dimensional (0D) double perovskite Cs2ZrCl6 has emerged as a promising lead-free phosphor due to its strong quantum confinement, excellent stability, and tunable luminescence. However, the conventional synthesis routes often rely on harsh conditions—such as high temperature, corrosive reagents, or complex vapor-phase method—that hinder the scalability and environmental sustainability. Herein, we report a green, room-temperature, and scalable strategy to synthesize the Cs2ZrCl6 microcrystalline powders, which involves the sequential addition of ZrCl4 and CsCl to ethanol under ambient stirring conditions. By simply introducing dopant precursors (e.g., TeO2, SbCl3, and BiCl3) or substituting CsCl with CsBr during synthesis, we achieve the versatile doped Cs2ZrCl6 with various cations (Te4+, Sb3+, and Bi3+) and anions (Br−) to realize the tunable broad spectral from blue to orange emission. Notably, this approach overcomes the long-standing challenge of halide (Br−) incorporation into Cs2ZrCl6, which is difficult via hydrothermal methods and costly via vapor deposition. Furthermore, in situ formation of a hydrophobic SiO2 layer through tetramethoxysilane hydrolysis enhances the moisture resistance, as evidenced by an increased water contact angle. This facile, low-cost, and eco-friendly methodology paves the way for the practical deployment of Cs2ZrCl6-based phosphors in lighting, displays, and radiation detection technologies.