Hydrogen-bond-driven synergistic regulation of crystallization and interfacial coupling in 1.85 eV wide-bandgap perovskites for high-performance organic tandem solar cells

Abstract

Wide-bandgap (WBG) perovskite solar cells (PSCs) serve as essential top cells in perovskite/organic tandem solar cells (POTSCs), where their optoelectronic properties profoundly impact overall device performance. However, WBG PSCs with high bromine content suffer from substantial energy losses due to inferior film crystalline and severe phase segregation, which hinder the advancement of efficient POTSCs. Herein, propanedioic acid (PPDA) is designed and adopted as a crystallization regulator to modulate the nucleation and crystal growth kinetics of 1.85 eV WBG perovskites. This strategy enhances film crystallinity and effectively suppresses phase segregation. Additionally, PPDA strengthens field-effect coupling at the perovskite surface through hydrogen bonding with the upper propane-1,3-diammonium iodide (PDAI2) interlayer, thereby significantly reducing the interfacial non-radiative voltage loss. Consequently, the 1.85 eV WBG PSC achieves a record power conversion efficiency (PCE) of 19.35% with an exceptional open-circuit voltage (VOC) of 1.38 V, along with great operational stability. When integrated with organic sub-cells in a two-terminal tandem configuration, the POTSC delivers an impressive PCE of 26.25% and a notable VOC of 2.22 V. This work elucidates a synergistic mechanism for simultaneous crystallization regulation and interface enhancement in perovskite photovoltaics, providing valuable insights for developing high-performance WBG and tandem devices.