Universal phase-based self-powered strain sensing in photovoltaic cells enabled by optoelectronic chromatic dispersion

Self-powered strain sensors that operate without external power are essential for autonomous monitoring in flexible electronics, robotics, and photovoltaic systems. We demonstrate a generic, phase-based strain-sensing mechanism based on optoelectronic chromatic dispersion (OED) in a standard silicon photovoltaic (PV) cell, requiring no dedicated fabrication, no external bias, and no modification of the device structure or operating point. Under intensity-modulated illumination, mechanical deformation induces a band-gap shift that alters the wavelength-dependent carrier-transport delay and is directly encoded in the modulation phase of the photocurrent. Operating near the silicon absorption edge at 980 nm yields a minimum detectable strain resolution of ≈ 2 μ ε / Hz at room temperature, in good agreement with theory. Because OED relies on universal semiconductor transport physics, this approach is material-agnostic, low-cost, and compatible with add-on deployment on working PV panels, opening new opportunities for self-powered, high-resolution strain sensing and in-situ structural diagnostics.