Multi-mode dynamic anti-counterfeiting and self-calibrated temperature sensing applications based on Bi/Mn -activated CaSb2O6 phosphor

Developing anti-counterfeiting materials that are easy to identify and difficult to imitate, as well as temperature-sensitive materials with high sensitivity and a wide detection range, remains a significant challenge—particularly for luminescent materials that integrate both functionalities. Herein, a series of CaSb 2 O 6 : Bi, Mn phosphors were synthesized by high-temperature solid-phase method, integrating multi-color dynamic anti-counterfeiting capability with multi-mode optical temperature sensing. By doping Bi 3+ ions, the blue light emission of Bi 3+ ions completely overlaps with the self-activated emission of the CaSb 2 O 6 host, greatly enhancing the blue light emission of the host. In addition, when Mn 2+ ions are added, due to the incomplete oxidation of Mn 2+ during the preparation process, both Mn 2+ and Mn 4+ ions coexist within the host. Under UV excitation, the CaSb 2 O 6 : Bi, Mn phosphors exhibit multi-color emission of cyan-green, blue, purple, and magenta, accompanied by persistent green emission originating from Mn 2+ ions, offering a potential approach for dynamic anti-counterfeiting applications. The temperature sensitivity characteristics of the phosphors were investigated based on the fluorescence intensity ratio technique, and a maximum relative sensitivity of 1.56 % K −1 was obtained at 383 K. Taking advantage of these material properties, an integrated dynamic anti-counterfeiting and encryption system was engineered, and a fiber-optic temperature sensing platform was established to monitor the real-time temperature of an electric hand warmer.