Excitation Wavelength-Dependent Multi-Emission in Sb3+/Bi3+/Er3+ Codoped Perovskite Toward Optical Anti-Counterfeiting and Information Storage

Inorganic lead-free halide perovskites are quite desirable for various applications due to their outstanding optoelectronic performances. However, excitation wavelength-dependent multi-emission in a single luminophore is less reported. In this study, Sb3+/Bi3+/Er3+ codoped Cs2Ag0.1Na0.9InCl6 lead-free double perovskite with upconversion and downshifting luminescence modes has been developed. The double perovskite displays a dual-emission band located at 450 nm and 580 nm under excitation of 355 nm. The blue emission originates from self-trapped excitons (STEs) in [SbCl6]3- octahedrons, while the yellow emission comes from STEs between states localized in the BiCl6 and AgCl6 octahedra. Interestingly, the phosphor's emission can be dynamically adjusted by excitation wavelength and Sb3+ doping concentration. Not only that, the phosphor can also generate upconversion green light upon the irradiation of 980 nm lasers. The multi-excitation wavelength characteristics of this perovskite make it very suitable as a material for anti-counterfeiting and encoded information storage, and the excellent temperature stability and moisture resistance of this perovskite also make it more promising.