One-Dimensional Sb2Se3 Enabling a Highly Flexible Photodiode for Light-Source-Free Heart Rate Detection

Accurate, real-time and non-invasive monitoring the health signals such as heart rate is indispensable for mobile health care. Highly sensitive and flexible photoelectric detector is the key component for collection of biological signal. Herein, a Sb2Se3-based photodiode is fabricated on flexible polyimide substrate. The device exhibited impressive detection performance with 95 dB linear dynamic range, 83% external quantum efficiency, 0.42 A W-1 photoresponsivity, less than 10-14 A Hz-1/2 noise current and 500 kHz -3dB bandwidth. Moreover, thanks to the 1D crystal structure of Sb2Se3, our devices demonstrate ultrahigh flexibility with negligible performance degradation after bending at 69 o for 1000-times cycles. Owning to these decent features, the flexible Sb2Se3 photodiodes are employed for additional-light-source-free heart rate detection. This work opens up an avenue towards wearable Sb2Se3-based photoelectric devices, such as flexible solar cells.