Researchers at The University of Tokyo have developed a semi-transparent solar cell. Instead of conventional silicon, the cell uses the organic-inorganic hybrid material perovskite to generate electricity. This material efficiently absorbs blue light, while nanocubes of metallic silver improve the capture of red light, letting visually important green light through. Because of the efficient light capture, the perovskite layer can be made very thin, improving its transparency. The cell could therefore be used to coat windows.