Mechanochemical synthesis of Sb³⁺-doped Cs₂ZrCl₆ double perovskites for excitation-wavelength-responsive trimodal luminescence and high-level anti-counterfeiting

All-inorganic lead-free halide perovskites have shown great promise in the field of optoelectronics. However, the room-temperature, low-cost, and large-scale synthesis of such materials remains challenging. Here, we report a rapid mechanochemical synthesis strategy based on ethanol-assisted ball milling to successfully prepare Cs₂ZrCl₆ double perovskite with Sb³⁺ doping, which exhibits tricolor luminescence with excitation wavelength-dependent characteristics. The material emits blue (450 nm, [ZrCl₆]^2- self-trapped exciton emission), warm white (450/610 nm dual peaks), and red (610 nm, Sb^{3+ 3}P₁ → ¹S₀ transition) light under 254, 310, and 365 nm ultraviolet excitation, respectively, with a photoluminescence quantum yield (PLQY) stably exceeding 30%. When the Cs₂ZrCl₆:Sb³⁺ samples are fabricated into anti-counterfeiting patterns, they emit blue, warm white, and red light under 254, 310, and 365 nm ultraviolet lamp excitation, respectively, demonstrating excellent application prospects in the field of anti-counterfeiting encryption. This study provides a new idea for the development of efficient and environmentally friendly synthesis of multi-modal anti-counterfeiting materials.