2D or Not 2D? Impact of Bulky Cation Deposition Method on Inverted Perovskite Solar Cells

= 2). In contrast, the antisolvent method results in surface and grain boundary passivation without the formation of a detectable separate 2D phase. This observation is further correlated with device performance, where passivation leads to improvement, while 2D phase formation does not. These results highlight the significant impact of the deposition method on the formation of the 2D layer over the 3D perovskite in inverted architectures, revealing that 2D phase formation is not always beneficial for device performance in inverted architecture solar cells.