First principles rationale of strain-induced modifications in hybrid double halide perovskite: optoelectronics and photovoltaic perspectives

Abstract

Strain engineering enables precise tuning of optoelectronic properties by altering structural design, energy levels, and band gaps through tensile or compressive strain in various directions. While tensile strain promotes ion migration by weakening bonds and lowering activation energy, applying external compressive strain can offset residual tensile strain in perovskite films, enhancing their efficiency and stability. In this study, we have explored the impact of strain on the optoelectronic and photovoltaic properties of (DMA)₂SnCl₆ [DMA = dimethylammonium ((CH₃)₂NH₂) cation] employing density functional theory (DFT). Strain levels of 2%, 4%, and 6% have been applied in both tensile and compressive modes. Notably, the band gap decreases with increasing strain, irrespective of type. Mechanical property analysis confirms the compound meets most Born stability criteria, ensuring structural integrity. A maximum efficiency of 29.28% under 6% tensile strain along the x-axis underscores the potential of strain engineering to enhance photovoltaic performance.