Modulation of Colloidal Assembly Behavior Enables Printable Low‐Dimensional Perovskite Photovoltaics

Abstract

AbstractThe multiple quantum wells (QWs) distribution in low‐dimensional perovskite films hinders charge transport due to the fundamental difficulty of controlling crystal growth from precursor solutions, yielding poorly homogeneous low‐dimensional perovskite solar cells (PSCs), especially in upscaling fabrication. Here, efficient low‐dimensional PSCs are realized by modulating the colloidal assembly behavior in the precursor solution to induce intermediate structures. In combination with in situ liquid time‐of‐flight secondary ion mass spectrometry, the assembly behavior of organic cations involved lead iodide‐dominated colloidal soft framework is visualized by investigating the precursor species differences under hydrogen bonding interactions. Subsequently, solid‐state reactions emerge and the formamidine (FA)‐based perovskite films exhibit significantly suppressed multiple QWs distribution. Encouragingly, the FA device (n=9, by meniscus‐assisted coating) achieves a power conversion efficiency (PCE) of 20.28 % for a size of 0.04 cm2 and a PCE of 15.35 % for a mini‐module of 16.94 cm2 with superior stability.