Highly Sensitive Perovskite Nanowire Photodetectors Enabled by Surface State Engineering for Non-Contact Heart Rate Monitoring.

Non-contact heart rate detection is essential in health monitoring, emphasizing the need for highly sensitive photodetectors to ensure accurate measurement. Nanowire photodetectors, benefiting from surface states, exhibit excellent performance. However, the distribution and charge-trapping capability of these surface states are primarily dictated by the intrinsic material properties, limiting tunability. Herein, a strategy is presented to optimize MAPbI3 nanowire photodetectors through surface state engineering with C60. The C60 forms electron depletion zones in the nanowires, reducing noise current by 74% and tripling the photoresponse. As a result, a remarkable specific detectivity of 6.7 × 1014 Jones is achieved, which represents the highest value reported for MAPbI3 nanowire-based photodetectors as far as this study knows. This high-performance photodetector facilitates non-contact heart rate monitoring, demonstrating the ability to reliably detect pulse wave signals, surpassing the capabilities of commercial silicon photodetectors. This study believes that this work provides a pioneering approach to surface state engineering, advancing nanowire-based photodetectors for health monitoring applications.