Benchmarking Inorganic Thin‐Film Photovoltaics Technologies for Indoor Applications

The growing demand for sustainable power solutions for Internet of Things (IoT) systems, projected to reach billions of units in the near future, highlights the limitations of battery reliance due to maintenance, environmental concerns, and supply constraints. Inorganic thin-film photovoltaics (PV) technologies (including cadmium telluride, kesterite, antimony chalcogenide, nanometric silicon, and elemental selenium) emerge as promising candidates for indoor applications due to their suitable bandgap energies and very high robustness and stability, as well as their potential to achieve higher efficiencies at indoor illumination conditions. The work reported here compares the optoelectronic performance of several technologies under relevant indoor illumination conditions using a consistent characterization methodology, that encompasses the needs of indoor PV, including a benchmark with commercial state-of-the-art (SoA) a-Si devices. The results show many devices performing surprisingly well indoors, which corroborates their potential for achieving high efficiencies. However, the performance of these devices is compromised at very low irradiance conditions, and this is attributed to the need for optimization of both the shunt resistance and saturation current density.