Excitation wavelength-dependent tunable color Te4+-doped Cs2ZrCl6 vacancy-ordered perovskites for optical anti-counterfeiting.

Te⁴⁺-doped Cs₂ZrCl₆ vacancy-ordered perovskites with excitation wavelength-dependent tunable color have been synthesised by a simple precipitation method at room temperature, with two luminescent centres originating from the Te⁴⁺ and the STE (self-trapping exciton) of the Cs₂ZrCl₆ itself, respectively. They exhibit two different emission characteristics at 254 nm and 365 nm excitation wavelengths. At an excitation wavelength of 254 nm, the emission characteristics allow Te⁴⁺-doped Cs₂ZrCl₆ to exhibit tunable emission from blue to white to yellow under the control of Te⁴⁺ doping. And the excitation wavelength of 365 nm shows yellow emission. Te⁴⁺ doped Cs₂ZrCl₆ phosphors were used for optical anti-counterfeiting, and the anti-counterfeiting patterns were well distinguished under 254 nm and 365 nm UV lamps, demonstrating the potential of this excitation wavelength-dependent tunable color material for optical anti-counterfeiting applications. [ABSTRACT FROM AUTHOR]