The Internet of Things (IoT) requires sustainable, battery-free power solutions. Micro energy harvesting captures ambient energy to enable self‑powered IoT nodes. Among all available sources, solar energy (photovoltaic harvesting) offers the highest power density and greatest maturity, making it the most practical choice for indoor and outdoor IoT deployments.
Thin-film solar cells are a type of solar cell made by depositing thin layers of photovoltaic material onto a glass, plastic or metal substrate. Thin-film solar cells are typically much thinner than the wafers used in conventional crystalline silicon based solar cells. Only seven years later in 1999, the U.S. National Renewable Energy Laboratory and Spectrolab collaborated on a three-junction gallium arsenide solar cell that reached 32% efficiency. In 2022, Vladimir Bulović's Organic and Nanostructured Electronics (ONE) Lab at the Massachusetts Institute of Technology (MIT) introduced flexible organic thin-film solar cells integrated into fabric.
Micro solar cells extend the operational lifespan of IoT wildlife trackers indefinitely, resolving the critical limitation of finite battery capacity in remote conservation efforts. By harvesting ambient light energy, these miniature photovoltaic cells eliminate the need for dangerous and expensive animal recapture operations to replace tracking hardware batteries.
