Highly sensitive fast-response near-infrared photodetectors based on triple cation Sn-Pb perovskite for pulse oximetry system

Blood oxygen saturation has emerged as a crucial physiological parameter following electrocardiography, respiration, and blood pressure measurements. In this study, high-quality low bandgap triple cation Sn-Pb perovskite films are fabricated, with the preferred orientation and extended light absorption edge as far as 961 nm. By double-side interfacial modification, the PPPB (poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/perovskite/[6,6]-phenyl-C61-butyric acid methyl ester/bathocuproine) near-infrared photodetector exhibits an enhanced photoresponse, with the ultra-fast response speed of 373 ns, wide linear dynamic range of 159 dB, high detectivity of 1.56 × 1011 Jones, and impressive responsivity of 190 mA W−1. Leveraging its exceptional photoelectric performance, the photodetector demonstrates its applicability in a pulse oximetry system, enabling the accurate and non-invasive assessment of heart rate and blood oxygen saturation across various physiological states. This work highlights the immense potential of our photodetector for real-time monitoring of blood oxygen saturation and heart rate.