Qihua Li studied the adsorption of water on several metal halide perovskites AMX3 using extensive geometries, energies and chemical bonding analysis within the DFT framework. In this work, Qihua focused on the impact of the compositional change in the adsorption strength of water on diverse halide perovskite surfaces. He reveals that the hydrophilic group NH3+ of MA+cation may be the cause for instability issues. We find that the adsorption of water on FAPbI3 and CsPbI3 are much weaker than on MAPbI3 due to the less polarity of FA+ and Cs+. When exchanging M2+ cations, water adsorption on MASnI3 is also less energetically favorable than on MAPbI3 because of the weaker ionic interaction of H2O-MASnI3. When exchanging X– anion, water adsorption on MAPbBr3 is slightly weaker than on MAPbI3 due to the slightly weaker covalent interaction of H2O-MAPbBr3.
The manuscript is recently accepted for publication by Applied Surface Science. The work provides a good starting point for future study on the degradation of perovskite films induced by the moisture.