Theoretical assessment of thermodynamic stability of 2D octane-1,8-diammonium lead halide perovskites

Two-dimensional (2D) lead halide perovskites are promising materials for photovoltaics due to a combination of excellent functional properties and improved stability as compared to their 3D analogues. A thermodynamic stability of the 2D octane-1,8-diammonium-based perovskites containing one to four layers has been assessed using a semi-empirical approach. Revealed values of the standard enthalpy of formation are essentially negative, while the dependence of enthalpy on the number of layers is not linear, so the perovskites with the even number of layers seem to be much more stable due to the features of their crystal and local structures.