Ultrahigh PLQY Lead‐Free Organic–Inorganic Hybrid Zirconium‐Based Perovskites in Anticounterfeiting Applications

Abstract Organic hybrid halide perovskite, which has excellent characteristics of low cost, nontoxicity, and high recognition, has attracted extensive attention in optical anticounterfeiting applications. In this paper, (TEA) 2 ZrCl 6 (TEA = tetraethylammonium) single crystals (SCs) are synthesized by an easy‐to‐operate hydrothermal method, which exhibits excitation wavelength‐dependent emission at 254 and 365 nm, respectively. Moreover, the photoluminescence quantum yield of (TEA) 2 ZrCl 6 SCs achieves 84.7%, with the introduction of Sb 3+ ions. (TEA) 2 ZrCl 6 and doped (TEA) 2 ZrCl 6 patterns can be recognized with excitation by different wavelengths. In addition, as‐prepared (TEA) 2 ZrCl 6 crystals show interesting radioluminescence for another anticounterfeiting model with the light yield of 17 709 photons per MeV. The experimental results indicate the novel (TEA) 2 ZrCl 6 SCs have a huge potential for X‐ray imaging and anticounterfeiting.