Researchers from Fraunhofer ISE have developed indoor solar cells with over 40 percent efficiency at 100 lux. The team optimized GaInP-based III-V semiconductors for improved performance under low light. N-doped GaInP cells showed higher efficiency than p-doped ones due to longer charge carrier lifetimes. This makes them suitable for powering autonomous indoor IoT devices without wired connections. Researchers tested different solar cell architectures to evaluate performance in artificial lighting conditions. The technology converts visible indoor light, such as from LEDs, into electricity efficiently. The work builds on results from three projects-“50Percent” funded by BMWK, “H2Demo” funded by BMBF, and “SMART” supported by AZUR SPACE and DLR. The findings were published in Applied Physics Letters and represent a major step in indoor photovoltaics development for smart device applications.Earlier this year, Fraunhofer ISE mapped a 500 GW agri-PV potential across Germany’s farmland.