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, Sb 3+ /Bi 3+ /Er 3+ codoped Cs 2 Ag 0.1 Na 0.9 InCl 6 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 [SbCl 6 ] 3- octahedrons, while the yellow emission comes from STEs between states localized in the BiCl 6 and AgCl 6 octahedra. Interestingly, the phosphor’s emission can be dynamically adjusted by excitation wavelength and Sb 3+ 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.