Photovoltaic Power Harvesting Technologies in Biomedical Implantable Devices Considering the Optimal Location

There are still many challenges in effectively harvesting and generating power for implantable medical devices. Most of today's research focuses on finding ways to harvest energy from the human body to avoid the use of batteries, which require surgical replacement. For example, current energy harvesters rely on piezoelectricity, thermoelectricity, and solar electricity to drive the implantable device. However, the majority of these energy harvesting techniques suffer from a variety of limitations such as low power output, large size, or poor efficiency. Due to their high efficiency, we focus our attention on solar photovoltaic cells. We demonstrate that the tissue absorption losses severely influence their performance. We predict the performance of these cells using simulation through the verified experimental data. Our results show that our model can obtain 17.20% efficiency and 0.675 V open-circuit voltage in one sun condition. In addition, our device can also harvest up to 15 mW/cm² in dermis and 11.84 mW/cm² in hypodermis by using 100 mW/cm² light source at 800 nm and 850 nm, respectively. We propose implanting our device in hypodermis to obtain a stable power output.