Low‐Temperature Chemical Bath Deposition of Conformal and Compact NiOXfor Scalable and Efficient Perovskite Solar Modules

Abstract A scalable and low‐cost deposition of high‐quality charge transport layers and photoactive perovskite layers are the grand challenges for large‐area and efficient perovskite solar modules and tandem cells. An inverted structure with an inorganic hole transport layer is expected for long‐term stability. Among various hole transport materials, nickel oxide has been investigated for highly efficient and stable perovskite solar cells. However, the reported deposition methods are either difficult for large‐scale conformal deposition or require a high vacuum process. Chemical bath deposition is supposed to realize a uniform, conformal, and scalable coating by a solution process. However, the conventional chemical bath deposition requires a high annealing temperature of over 400 °C. In this work, an amino‐alcohol ligand‐based controllable release and deposition of NiO X using chemical bath deposition with a low calcining temperature of 270 °C is developed. The uniform and conformal in‐situ growth precursive films can be adjusted by tuning the ligand structure. The inverted structured perovskite solar cells and large‐area solar modules reached a champion PCE of 22.03% and 19.03%, respectively. This study paves an efficient, low‐temperature, and scalable chemical bath deposition route for large‐area NiO X thin films for the scalable fabrication of highly efficient perovskite solar modules.