Oxide Heterostructures for Efficient Solar Cells

We propose an unexplored class of absorbing materials for high-efficiency solar cells: heterostructures of transition-metal oxides. In particular, LaVO3 grown on SrTiO3 has a direct band gap similar to 1.1 eV in the optimal range as well as an internal potential gradient, which can greatly help to separate the photo-generated electron-hole pairs. Furthermore, oxide heterostructures afford the flexibility to combine LaVO3 with other materials such as LaFeO3 in order to achieve even higher efficiencies with band-gap graded solar cells. We use density-functional theory to demonstrate these features. DOI: 10.1103/PhysRevLett.110.078701