Multiwavelength Responsive Luminescence for Temperature Sensing and Visualized Information Encoding/Decoding Based on Er3+/Tb3+-Doped Ba2Ga2GeO7 Phosphors

The rational exploration of lanthanide-doped phosphors is of great significance for realizing precise optical temperature sensing and information security applications. Here, triple-wavelength responsive Ba2Ga2GeO7:Er3+ phosphors were synthesized by a solid-state method, and the samples gave highly pure green emissions under 808 and 382 nm excitations. Within the temperature range from 313 to 573 K, the corresponding temperature sensing performance based on the fluorescence intensity ratio was estimated, and the maximum relative sensing sensitivities were determined to be 0.97%, 1.20%, and 1.19% K–1 for the 980, 808, and 382 nm excitations, respectively, indicating the title materials are promising for use in temperature sensors. Furthermore, the introduction of Tb3+ enables the materials to realize down conversion luminescence and long persistent luminescence, which greatly enrich the luminescence phenomena of the samples. Based on the abundant emission modes, novel information encryption strategies of digital displays and binary digital-ASCII multiplex codes are proposed, which provide reliable guidance on advanced visualized information encryption.