Ultrafast self-powered strain sensor utilizing a flexible solar cell

In the era of the rapidly growing Internet of Things (IoT), self-powered strain sensors play a vital role in ensuring the structural health of equipment and enabling intelligent monitoring systems. While integrating photovoltaic cells with sensing arrays to create self-sustaining sensing systems that operate continuously without external charging is promising, the design involving distinct sensors and energy-generating devices connected via conditioning circuits can pose integration challenges. Therefore, our novel approach of using copper indium gallium selenide (CIGS) solar cells directly as self-powered strain sensors excels in reducing system complexity. Density functional theory (DFT) calculations used to evaluate the effects of strain on the bandgap of the material showed downward trends under tensile and compressive loads. COMSOL Multiphysics simulations using the DFT results confirmed a direct correlation between strain and the device output voltage changes, establishing the working principle of the strain sensor. The CIGS sensor exhibits high linearity, low hysteresis, and an ultrafast response (0.03 ms) under impact tests. Environmental impact assessments lead to corrective measures to enhance the performance reliability. A distributed CIGS strain sensor network was able to successfully monitor wing deformation and can measure vibrations up to 20,000 Hz, marking significant progress toward practical applications in self-powered structural health monitoring.