Thermally induced optical coding and encryption based on Y ₂ W ₃ O ₁₂ :Tb ³⁺ /Eu ³⁺ ceramics

ABSTRACT Recent advances in inorganic negative thermal expansion (NTE) materials have highlighted their potential for multifunctional applications, yet challenges remain in optimizing their luminescent properties for practical use. Based on Y 2 W 3 O 12 :Tb 3+ /Eu 3+ NTE ceramics, we present a thermally regulated optical encoding and encryption approach. Under 254 nm UV excitation, the distinctive high‐temperature thermal enhancement effect of red emission and the thermal quenching phenomenon of green emission were discovered in these ceramics, enabling an effective temperature‐controlled color change phenomenon. Optical information encoding and readout were realized through the synergistic modulation effect of UV light and heat, and the encryption and decoding process of multivariate codes and alphabets at high temperatures was accomplished. The encoding was accomplished by modulating the Tb 3+ /Eu 3+ doping concentration ratio and regulating the luminescent color of the ceramics over a wide range. Furthermore, the ceramic demonstrates a wide temperature range of 363‒603 K for temperature sensing effect. This offers a research idea for achieving multifunctional ceramics of coding and temperature sensing.