Multicolor mechanoluminescence for integrated dual-mode stress and temperature sensing

Abstract

The advancements in the new industrial era demand higher standards for integrated intelligent sensors. These multi-parameter coupling sensors require sensing materials that can swiftly respond to various physical stimuli, including stress, temperature, humidity, etc. Mechanoluminescence (ML), with its unique mechanical–optical response, serves as an effective medium for stress sensing. In ML materials, constructing multiple luminescent centers not only enables multicolor ML but also allows for temperature sensing through the differential thermal quenching properties of various luminescent centers. In this study, we present an energy transfer strategy that leverages high-energy blue-emitting ML from the host material, combined with Tb³⁺ and Mn²⁺, to achieve multicolor ML. The mechanical response is correlated with the integrated intensity of ML, while the temperature response is governed by the dynamic ML intensity ratio of I_Tb/I_Mn. This approach simplifies the design of multifunctional sensors and facilitates remote, dual-mode sensing. Moreover, we develop a highly secure encryption system based on the integration of multicolor PL and ML with an ML-triggering mechanism that is both convenient and reliable. This work presents an effective strategy for developing multicolor ML materials and advancing multimodal sensing.