Study of the effect of temperature on light-induced degradation in methylammonium lead iodine perovskite solar cells

In this paper, the effect of temperature on the process of optical degradation of CH3NH3PbI3 perovskite solar cells is studied. First, we promote the theory of the degradation process we have already presented, which leads to more accurate results. Previously, in the proposed model, we had considered the density of the vacancies distributed in the perovskite layer to be constant, while in reality, their density changes over time. In order to obtain the electric field resulting from the migration of vacancies, which is, in fact, the cause of the optical degradation of the perovskite solar cells, we need the initial density of the vacancies and its temperature dependence as well as migration energy (potential barrier against the migration) of the vacancies. Using the Gibbs free energy resulting from the formation of the vacancies, the density of the vacancies is obtained. Also, by calculating the changes in electrostatic energy between the lattice ions during displacement, the migration energy is obtained. When the required parameters are presented, the temperature dependence of the optical degradation process is discussed using the proposed theory, and the results show the appropriate accuracy of this theory.