Flexible Optical Fiber Stress/Temperature Dual-Mode Sensing Based on CaZnOS:Nd,Er

Mechanoluminescence (ML) and upconversion luminescence (UCL) materials exhibit significant potential in advanced optical sensing applications. However, single-function luminescent materials often fail to meet the increased complexity and precision demands of modern application scenarios. Here, flexible optical fiber based on ML and UCL dual-mode luminescence is demonstrated in Ca/SrZnOS: Nd³⁺, Er³⁺, which can be integrated into potential dual-mode stress and temperature sensing devices. After 4200 cycles of 2 N load, the ML intensity remaines at ≈67% of its initial value. Additionally, such device has a temperature sensitivity of 1.423% K⁻¹ at 273.15 K, with a detection accuracy of 1.1990 °C. The device maintained excellent cycling stability over a broad temperature range (0–80 °C), as evidenced by the unchanged FIR values after 10 cycles. The device demonstrates potential applications in remote stress and temperature monitoring, particularly in high-temperature, high-pressure, or hazardous environments, where optical fiber transmission ensures both safety and accuracy.