Initializing Compression Stress to Stabilize the Phase Homogeneity in Bifacial Semitransparent Perovskite Solar Cells

Abstract Semitransparent perovskite solar cells (ST‐PSCs) hold great promise for various commercial applications, including building integrated photovoltaics and tandem solar cells. The all‐inorganic perovskite, known for its outstanding optical transparency and thermal stability, emerges as a top contender for ST‐PSCs. However, challenges persist due to phase segregation, which hampers charge carrier transport and operational stability. In this study, an approach is proposed to address these challenges by employing strain engineering to reconstruct the perovskite texture, eliminating inhomogeneities within the perovskite film. The crucial role of compressive strain in stabilizing lattice rigidity and suppressing light‐induced ion migration is demonstrated. Furthermore, a transparent light‐harvesting architecture is devised utilizing a sandwiched layer of gold embedded between MoO 3 . This design enhances power generation by efficiently harnessing incident light from both the front and rear panel surfaces. Therefore, bifacial ST‐PSCs achieve an equivalent efficiency ( η eq ) of 13.97% with an average visible light transmittance of 41.58%, yielding an outstanding light utilization efficiency of up to 5.8%. This research not only advances the understanding of perovskite material phase‐segregation behavior but also introduces an effective strategy for enhancing optical gain without compromising the semitransparent characteristics.