A flexible photovoltaic wristband for self-powered wearable sensing on the human body

With the continuous integration of functions in wearable devices, power consumption demands have increased significantly, posing serious challenges to conventional power supply methods. Wearable self-powered technologies offer an effective solution to this issue. This study focuses on the efficient utilization of solar energy from the human wrist and presents the design and implementation of a flexible photovoltaic wristband. The wristband employs a multi-directional parallel array of photovoltaic cells, integrated with an energy management module, enabling it to adapt effectively to the dynamic and non-uniform solar irradiance conditions on the wrist. Through both simulated sunlight and real outdoor environment tests, the energy harvesting and load-driving performances of the photovoltaic wristband were comprehensively evaluated. The results show that under a highest average outdoor illuminance of 37.38 × 10³ lx (525 W·m⁻²), the wristband delivers an average output power of 15.88 mW, providing a stable 3.3 V supply to a wearable motion sensing node, thereby enabling self-powered operation. During a complete “energy accumulation-load activation” cycle, the sensing node can operate for 37.84 s to perceive and transmit data. By employing a one-dimensional convolutional neural networks (1D-CNN) algorithm, accurate recognition of four motion states is successfully achieved. This work presents a systematic study covering energy harvesting scenarios analysis, wristband design, performance evaluation, and sensing application. The proposed photovoltaic wristband demonstrates excellent cyclic energy accumulation and stable power supply capabilities, validating the feasibility and practicality of the wearable photovoltaic self-powered system and highlighting its promising potential for future wearable applications.