Uniform Permutation of Quasi-2D Perovskites by Vacuum Poling for Efficient High-Fill-Factor Solar Cells

摘要

The vertically ordered (small-to-large n) quasi-2D perovskite films serve as common approaches to facilitate directional charge transfer. Here, we report a different strategy of uniformly arranging different-n-value nanoplates (PEA_2MA_(n-1)Pb_2I_(3n+1)) by introducing vacuum poling treatment to enforce nucle-ation during crystallization. This uniform distribution is verified by delicate mechanical tape-peeling method while monitoring optical absorption, photolu-minescence (PL), and energy-dispersive X-ray spectroscopy (EDS). With uniform distribution, efficient carrier transfer within 10 ps is revealed by transient absorption. Moreover, record-high fill factor (FF) of 82.4% with power conversion efficiency (PCE) of 18.04% (Voc = 1.223 V, Jsc = 17.91 mA/cm~2) was demonstrated. Superior stability is achieved with retaining 96.1% of initial efficiency after 8-month storage and maintaining 97.7% at 80℃ for over 180 h. This uniformly arranging different-n-value nanoplates offers a new material engineering strategy to enhance carrier transfer and extraction for developing high-efficiency and stable quasi-2D perovskite solar cells.