Researchers have explored the bulk photovoltaic effect in a promising material for next-generation solar harvesting technologies. The bulk photovoltaic (BPV) effect is an uncommon phenomenon that may enable certain materials to outperform the conventional p–n junctions used in solar cells. In a new study, researchers from Japan have experimentally demonstrated the BPV effect in alpha-phase indium selenide (α-In2Se3) for the first time along the out-of-plane direction, validating previous theoretical predictions. The remarkable conversion efficiency recorded in their α-In2Se3 device signals a promising advancement for future solar cell technologies and photosensors. Understanding the bulk photovoltaic effect in solar cells A firm understanding of the photovoltaic effect, by which light can be converted into useful electrical energy, lies at the core of solar design and development. Today, most solar cells employ p–n junctions, leveraging the photovoltaic effect at different materials’ interfaces. However, these designs are constrained by the Shockley–Queisser limit, which hard-caps their theoretical maximum solar conversion efficiency and imposes a trade-off between the voltage and current that can be produced via the photovoltaic effect. Despite this, …