Photovoltaic Effect Goes Symmetric

M ost photovoltaic devices used to power homes, offices, rural infrastructure, and satellites generate electricity at the junction between two differently doped semiconductors. But certain undopedmaterials—those whose crystal structures are nonsymmetric about a central axis—can also generate light-induced currents via a phenomenon called the bulk photovoltaic effect. Yuya Ikeda and his colleagues at the University of Tokyo now demonstrate that appropriately polarized light can induce photocurrents in a bulk material that lacks these symmetry requirements [1]. Their simulations could broaden the field of bulk photovoltaics to crystalline materials of any symmetry group, potentially leading to more-efficient power conversion devices.