Temperature- and component-dependent degradation of perovskite photovoltaic materials under concentrated sunlight

We report on accelerated degradation testing of MAPbX₃ films (X = I or Br) by exposure to concentrated sunlight of 100 suns and show that the evolution of light absorption and the corresponding structural modifications are dependent on the type of halide ion and the exposure temperature. One hour of such exposure provides a photon dose equivalent to that of one sun exposure for 100 hours. The degradation in absorption of MAPbI₃ films after exposure to 100 suns for 60 min at elevated sample temperature (∼45-55°C), due to decomposition of the hybrid perovskite material, is documented. No degradation was observed after exposure to the same sunlight concentration but at a lower sample temperature (∼25°C). No photobleaching or decomposition of MAPbBr₃ films was observed after exposure to similar stress conditions (light intensity, dose, and temperatures). Our results indicate that the degradation is highly dependent on the hybrid perovskite composition and can be light- and thermally enhanced. (Chemical Equation Presented).