The bulk photovoltaic (BPV) effect is a rare phenomenon that could allow certain materials to surpass the performance of traditional p–n junctions in solar cells. In a recent breakthrough, researchers in Japan have experimentally confirmed the BPV effect in alpha-phase indium selenide (α-In2Se3) along the out-of-plane direction for the first time, aligning with prior theoretical predictions. The impressive conversion efficiency achieved in their α-In2Se3 device represents a significant step forward for next-generation solar cell technologies and photosensors.