Temperature dependence of iodine vacancies concentration in CH3NH3PbI3 perovskite: A theoretical analysis

H Shahivandi and M Nosratjoo, PHYSICA B-CONDENSED MATTER, 683, 415884 (2024).

DOI: 10.1016/j.physb.2024.415884

In this study, we investigate the temperature dependence of iodine vacancies in the organic -inorganic hybrid perovskite CH 3 NH 3 Pb I 3 through theoretical analysis. Iodine vacancies, as point defects, play a crucial role in the instability of perovskite solar cells. By employing molecular dynamics (MD) simulations, we calculate the formation energy of vacancies and examine its relationship with temperature. Our results reveal that the formation energy remains constant irrespective of temperature. However, elevated temperatures facilitate the provision of energy necessary for vacancy formation. To accurately determine the vacancy concentration, it is essential to consider the associated entropy changes. Analytical methods are employed to assess these entropy changes, offering valuable insights into the vacancy formation process. Utilizing the derived values, we quantify the concentration of vacancies and analyze their dependence on temperature. The findings obtained from this research contribute significant insights into the behavior of iodine vacancies within the studied CH 3 NH 3 Pb I 3 perovskite system.

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