Credit: Stephen Jesse/Oak Ridge National Laboratory, U.S. Dept. of Energy
The ORNL team used atomic force microscopy to characterize ionic movement at a solar material’s surface. Using other microscopy techniques, spectroscopy and simulations, they analyzed ionic movement deeper down, revealing ionic movement across grain boundaries where iodine and chlorine compete to bond with a methyl ammonium functional group. Because iodine coordinates with methyl ammonium better than chlorine, the chlorine is more likely to migrate when an electric field is applied.