Highly Efficient Perovskite Solar Modules by Scalable Fabrication and Interconnection Optimization

To push perovskite solar cell (PSC) technology toward practical applications, large-area perovskite solar modules with multiple subcells need to be developed by fully scalable deposition approaches. Here, we demonstrate a deposition scheme for perovskite module fabrication with spray coating of a TiO₂ electron transport layer (ETL) and blade coating of both a perovskite absorber layer and a spiro-OMeTAD-based hole transport layer (HTL). The TiO₂ ETL remaining in the interconnection between subcells significantly affects the module performance. Reducing the TiO₂ thickness changes the interconnection contact from a Schottky diode to ohmic behavior. Owing to interconnection resistance reduction, the perovskite modules with a 10 nm TiO₂ layer show enhanced performance mainly associated with an improved fill factor. Finally, we demonstrate a four-cell MA_0.7FA_0.3PbI₃ perovskite module with a stabilized power conversion efficiency (PCE) of 15.6% measured from an aperture area of ∼10.36 cm², corresponding to an active-area module PCE of 17.9% with a geometric fill factor of ∼87.3%.