Researchers at the Los Alamos National Laboratory (LANL) in New Mexico, USA have found out why perovskite solar cells degrade in sunlight, as well as how the devices can “self-heal” by being given time in the dark. The research, that determined that photo-degradation in perovskite cells is a purely electronic process due to charge accumulation without chemical damage to the crystal structure, could help catalyze the promising solar technology.

The new finding, that organometallic halide semiconducting perovskite solar cells degrade under continuous sunlight but recover in the dark is seen as very good news as it means the process is of physical nature rather than chemical decomposition. According to the researchers: “After extensive characterization electronically and optically, we found it was the charge accumulation in the cell that reduces the photo-generated electrical current. Our team predicts the charge accumulation is initiated by the charged trap states, called small polaron states, which is only activated under light.”