Mn and Cu codoped Cs2ZnBr4metal halide with multiexcitonic emission toward anti-counterfeiting.

The growing demand for optical anti-counterfeiting technology requires the development of new environmentally-friendly smart materials with single-component, multimodal fluorescence. Herein, Cs2ZnBr4:0.3Mn2+&0.15Cu+, as an efficient multimodal luminescent material with excitation-wavelength-dependent emission is reported. Under 365 nm and 254 nm UV light excitation, Cs2ZnBr4:Mn2+&Cu+emits mutually independent green light at 525 nm and blue light at 470 nm, which origin from the emission of Mn2+and the Cu+enhanced self-trapped excitons of Cs2ZnBr4, respectively. Furthermore, the multiexcitonic emission is applied to anti-counterfeiting applications and information encryption and decryption engineering. This codoped strategy provides a colorful step to expand the new metal halide materials in fluorescent anti-counterfeiting and information encryption and decryption.