Resolving spatial and energetic distributions of trap states in metal halide perovskite solar cells
(PHYSorg.com Physics)

In a new report published on Science, Zhenyi Ni and a research team in applied physical sciences, mechanical and materials engineering and computer and energy engineering in the U.S. profiled spatial and energetic distributions of trap states or defects in metal halide perovskite single-crystalline polycrystalline solar cells. The researchers credited the photovoltaic performance of metal halide perovskites (MHPs) to their high optical absorption coefficient, carrier mobility, long charge-diffusion length and small Urbach energy (representing disorder in the system). Theoretical studies have demonstrated the possibility of forming deep charge traps at the material surface due to low formation energy, structural defects and grain boundaries of perovskites to guide the development of passivation techniques (loss of chemical reactivity) in perovskite solar cells. Charge trap states play an important role during the degradation of perovskite solar cells and other devices. Understanding the distribution of trap states in their space and energy can clarify the impact of charge traps (defects) on charge transport in perovskite materials and devices for their optimal performance.