Regulating crystallization kinetics in high-performance perovskites solar modules via vapor seed layer engineering

Abstract

Large-area fabrication of α-FAPbI₃ perovskite solar modules (PSMs) faces challenges in achieving uniform crystallinity and minimizing grain boundary defects. Herenin, a CsPbBr₃ seed layer was introduced onto the NiOx hole transport layer (HTL) via vacuum evaporation prior to perovskite film deposition using a vapor-blade coating method. Synchrotron-based in situ GIWAXS analysis revealed that the CsPbBr₃ seed layer effectively modulates the crystallization kinetics of PbI₂, facilitating the transition from δ-phase to α-phase perovskite and yielding films with superior crystallinity, grain size, and structural orientation. This seed layer also enhances the conductivity of NiOx, improves charge transport efficiency, and reduces recombination losses. As a result, large-area PSMs (active area: 61.56 cm²) incorporating the CsPbBr₃ seed layer achieved a power conversion efficiency (PCE) of 20.02 %, compared to 17.62 % for pristine devices. Additionally, these encapsulated modules exhibited excellent ambient stability, maintaining over 80 % of their initial performance after 1100 h under 60 % relative humidity. This study highlights the potential of CsPbBr₃ seed layer engineering as a scalable and effective strategy for industrial production of high-efficiency, stable perovskite solar modules