Ultralow-Drift Perovskite Detector for Multiple Vital Sign Fusion Monitoring

Metal halide perovskites hold significant promise for photoplethysmography (PPG)-based vital sign monitoring owing to attractive optoelectronic properties. The high signal-to-noise ratio (SNR) is critical for a PPG sensor to ensure the fidelity of the acquired signals. However, it is often limited by dark current drift due to intrinsic defects and ion migration within perovskites. To address this, we developed a charge anchoring strategy (CAS), which effectively suppresses dark current drift in MAPbBr3 single-crystal photodetectors. The resulting device achieved an ultralow drift of 6.60 × 10-8 nA mm V-1 s-1, outperforming most commercial silicon devices (7.90 × 10-7 nA mm V-1 s-1). This reduction in baseline drift yields a higher SNR, thereby remarkably improving PPG signal fidelity. Furthermore, the ultralow-drift CAS photodetector was incorporated into a self-built PPG acquisition system, enabling monitoring of multiple physiological parameters. This work offers a viable route to advancing perovskite photodetectors for collaborative multiparameter monitoring via PPG technology.