High-performance flexible Sb ₂Se ₃ thin-film photodetector for tunable color imaging and wearable physiological monitoring applications

Antimony selenide (Sb₂Se₃) has recently made considerable advancements in photovoltaic, photoelectrochemical, and photodetector research scenarios, owing to its advantageous material merits and superior optoelectronic properties. By contrast, the exploration of flexible Sb₂Se₃ photoelectric devices are less attempted, though it possesses unique one-dimensional (1D) crystal structure to enable large deformation tolerance. Here, we develop a flexible Sb₂Se₃ thin-film photodetector on polyimide substrate. Thanks to the high-quality Sb₂Se₃ light absorber and benign interfaces at both back contact and heterojunction regions, the carrier dynamics are effectively optimized. The leading flexible Sb₂Se₃ photodetector showcases self-powered and broadband features, with exceptional responsivity of 0.51 A·W^–1 and realistic detectivity up to 1.32 × 10¹³ Jones, ultra-fast response speed of 49 ns/351 ns of rise and decay times, and remarkable mechanical deformation stability, flourishing the high-level development for flexible Sb₂Se₃ photodetectors. Interestingly, a tunable single/dual-color flexible imaging system under band alignment modulation, along with a wearable and accurate heart rate/arterial blood oxygen saturation photoplethysmography detection system highlights the great application potential for flexible Sb₂Se₃ photodetectors.