How Lattice Strain Affects Nonradiative Recombination and Mobility in FAPbI₃

The lattice strain resulting from the fabrication process in hybrid organic-inorganic halide perovskites (HOIPs) and its dynamic changes under illumination are the key factors that affect the efficiency and intrinsic stability of HOIP-based solar cells. However, there is still a lack of comprehensive and in-depth understanding regarding how lattice strain influences the dynamic behavior and transport properties of charge carriers in organic-inorganic halide perovskites (HOIPs), as well as how light illumination triggers lattice strain. Here, our simulation results indicate that a 1% compressive stress delays hot electron cooling and increases the electron mobility by around 50%, while a 1% tensile stress accelerates cooling and reduces the electron mobility by about 37%. Additionally, both compressive and tensile strains accelerate electron-hole recombination. These important phenomena are mainly attributed to the modulation effect of strain on the thermal vibration of the lattice and the energy-level redistribution. Additionally, the research also reveals that the photoinduced dynamic lattice strain is due to the changes in Pb-I bonds jointly driven by the electron-phonon interaction and anharmonic lattice characteristics of HOIPs. This work provides new and systematic insights into the influence of strain on carrier dynamics and transport properties in HOIPs, which holds significant implications for enhancing the efficiency and stability of HOIP-based solar cells.