JACS: Computational Simulation Study of the Stability and Optoelectronic Properties of MAPbI3 Material
Release Date:
2020-08-05 14:27
Source:
Exposure of CH3NH3PbI3 perovskite materials to oxygen and light reduces their chemical stability. In light of this, Long Run and colleagues at Beijing Normal University reported a study on CH3NH3PbI3 that investigated the relationships among its degradation behavior, carrier lifetime, and the oxidation states of oxygen species.
Non-radiative molecular dynamics simulations combined with time-domain density functional theory reveal that neutral oxygen molecules have no impact on the stability of perovskite materials; however, superoxide and peroxide species can significantly accelerate the degradation rate of Pb–I chemical bonds in perovskites and enhance atomic fluctuations. By introducing electron and hole defect sites, the carrier lifetimes associated with neutral oxygen and superoxide species are reduced by 1–2 orders of magnitude.
Of particular importance is that photoexcited oxygen reduction to hydrogen peroxide eliminates defects and doubles the carrier lifetime, a phenomenon attributed to reduced non-radiative coupling and shortened quantum coherence. Computational simulations indicate that special care must be taken to prevent the introduction of superoxide ions, as these species can degrade the stability and optical properties of perovskites. This simulation approach not only elucidates the relationships among environmental conditions, light-induced effects, and the performance of perovskite materials, but also provides broad theoretical support for designing high-performance solar cells by predicting the behavior of analogous processes in other photovoltaic materials.
Related News