Strain in Metal Halide Perovskites: The Critical Role\nof A‑Site Cation

Abstract

We\ninvestigate the role of the A-site cation in the lattice strain\nof metal halide perovskites (MHPs) upon light illumination and heatingtwo\ninevitable factors during the operation of photovoltaic devices. We\nreveal that the A-site cation plays an important role in light-induced\nstrain in MHPs. Density functional theory calculations indicate that\nhydrogen-bonding interactions and ionization energy of the A-site\ncation are potential reasons responsible for the light-induced lattice\nstrain in MHPs. These findings offer an approach to modulate the light-induced\nstrain in MHPs, which is critical for further improving the efficiency\nand stability of MHP photovoltaics.