A spatial structure regulation strategy modulated the solubility and compactness of novel face-on oriented bisphosphonate-anchored SAMs for efficient inverted perovskite solar cells

Abstract

The dramatic development of monophosphate self-assembled molecules (SAMs) with novel molecular structures has significantly improved the power conversion efficiency (PCE) of inverted perovskite solar cells (PSCs). To date, face-on oriented bisphosphonate-anchored self-assembled molecules (D-SAMs) have not been attempted for application in PSCs, and adjusting intermolecular π–π interactions and molecular dipole moments via molecular design to obtain face-on oriented and tightly assembled D-SAMs is crucial for achieving high PCEs. Herein, a spatial structure regulation strategy was used to optimize the solubility and compactness of novel face-on oriented D-SAMs, thereby achieving a remarkable PCE of 25.81% and a fill factor (FF) of 86.92% in inverted PSCs based on TDT—this performance represents the highest efficiency reported to date for PSCs using D-SAMs as hole-transporting layers (HTLs). Furthermore, perovskite solar modules yielded a high PCE of 22.53%. Notably, under 3000 h of illumination using a solar simulator, unencapsulated TDT-based devices retained 93.04% of their initial PCE. This spatial structure regulation strategy presents a prospective approach for the further molecular design of new D-SAMs in PSCs.