In a work supported by the Department of Energy (DOE) and Office of Science, Basic Energy Sciences (BES), researchers from Stanford, University Pennsylvania, SLAC National Accelerator Lab, Columbia University, Carnegie Institute for Science in Washington and Weizmann Institute of Science in Israel, have shown how atoms in perovskites respond to light and could explain the high efficiency of these perovskite-based solar cells.

The team explains that sunlight causes large changes to the underlying network of atoms that make up perovskites. Before being hit with light, six iodine atoms rest around a lead atom. Within 10 trillionths of a second after being hit with light, the iodine atoms whirl around each lead atom. These first atomic steps distort the structure and result in significant changes. Furthermore, the atoms’ motions alters the way electricity flows and may help explain the efficiency of perovskites in solar cells.

University of Tokyo researchers have studies the structure of organometal halide perovskites, a ubiquitous class of solar cells and came up with interesting results.

Dr. Tae Woong Kim: “Until now, it has been believed each crystal phase of the perovskite solely exists at its given temperature range. However, in this research, we revealed their crystal phases coexist at room temperature and the coexistence induces self-organized superlattice structure. These evidences overturn the conventional theory. Especially, the existence of the spontaneous superlattice will maximize their potential for wide and diverse applications.”