Researchers at the University of California, Los Angeles have used a polymer film to reduce defects in the light-absorbing perovskite, producing solar cells that are efficient and relatively robust.

The team explains that perovskites usually used in solar cells typically contain an organic cation and lead halide anions. But the heat treatment used to convert the perovskite’s precursors into a crystalline layer can also drive out some of these organic cations. This leaves defects in the material’s structure that hamper its performance and potentially make it less stable to moisture, heat, and even sunlight itself.