Abstract:The solution processibility of perovskites provides a cost-effective and high-throughput route for fabricating state-of-the-art solar cells. However, the fast kinetics of precursor-to-perovskite transformation is susceptible to processing conditions, resulting in an uncontrollable variance in device performance. Here, we demonstrate a supramolecule confined approach to reproducibly fabricate perovskite films with an ultrasmooth, electronically homogeneous surface. The assembly of a calixarene capping layer on precursor surface can induce host–guest interactions with solvent molecules to tailor the desolvation kinetics, and initiate the perovskite crystallization from the sharp molecule–precursor interface. These combined effects significantly reduced the spatial variance and extended the processing window of perovskite films. As a result, the standard efficiency deviations of device-to-device and batch-to-batch devices were reduced from 0.64–0.26% to 0.67–0.23%, respectively. In addition, the perovskite films with ultrasmooth top surfaces exhibited photoluminescence quantum yield > 10% and surface recombination velocities < 100 cm s−1 for both interfaces that yielded p-i-n structured solar cells with power conversion efficiency over 25%.