Investigation of Additive‐Driven Film Formation and Performance in Hybrid Two‐Step Perovskite Solar Cells

Hybrid two‐step fabrication methods combining physical vapor deposition of a precursor layer with a subsequent solution‐based step offer distinct advantages for the formation of high‐quality perovskite thin films. Notably, this approach avoids toxic solvents and enables conformal coating, making it particularly attractive for integration into silicon‐based tandem solar cells. In this work, we fabricate and comprehensively characterize such perovskite solar cells (PSCs) using a suite of dedicated analytical techniques. A small amount of dimethyl sulfoxide (DMSO) within the solution step significantly enhances the quality of the resulting perovskite thin film, leading to improved device performance. The addition of DMSO results in improved conversion of the precursor to the perovskite phase, reduced residual lead iodide, and more efficient charge extraction. Furthermore, perovskite crystallization under a controlled atmosphere with 40% relative humidity leads to a marked increase in charge carrier lifetime, which correlates with higher power conversion efficiency. These findings highlight the potential of hybrid processing routes for scalable, high‐performance PSC manufacturing.