Ultrafast hole transfer mediated by a conjugated self-assembled molecule enables efficient and stable wide-bandgap perovskite solar cells

Charge accumulations and electron recombination at the interfaces between perovskites and charge transporting materials are two critical factors significantly hindering the power conversion efficiency (PCE) and device stability of wide-bandgap perovskite solar cells (WBG PSCs). Herein, we tailor-made a self-assembled molecule (SAM), termed XS13, featuring an enlarged π-donor and a π-linker, to regulate the interface carrier dynamics in ∼1.8 eV WBG PSCs. Ultrafast spectroscopy clearly demonstrated that the XS13 facilitated the rapid extraction and transfer of photo-generated holes compared to the reference SAM-2PACz. Consequently, WBG PSCs based on XS13 achieved an outstanding PCE of up to 19.20 %, surpassing that of control devices (16.41 %). Furthermore, XS13-based WBG PSCs exhibited a remarkable suppression of light/electricity-induced halide ions migration, leading to significantly improved device stability. Our findings offer a new strategy for the rational design of hole transporting molecules with controlled properties to enhance device performance of PSCs.