N‐Type Doping Characteristics Enabled by 1D Perovskite for Advancing Perovskite Photovoltaics: From 1.55 to 1.85 eV Bandgap

Abstract Developing low‐dimensional perovskites to enhance both single‐junction and tandem solar cells is of great interest for improving photovoltaic performance and durability. Herein, a novel 1D perovskite based on 1,3‐thiazole‐2‐carboximidamide (TZC) cation is introduced, which exhibits robust chemical interactions with PbI 2 and 3D perovskite, enabling the fabrication of high‐quality mixed‐dimensional perovskite films identified by both HR‐TEM and GIWAXS analyses. Benefiting from the lower formation energy barrier of 1D perovskites, they can preferentially form and act as crystal seeds to regulate perovskite crystallization kinetics with optimized morphology and improved crystallinity. In addition to effectively passivating surface defects and suppressing nonradiative recombination, TZC‐enabled 1D perovskites exhibit pronounced n‐type doping characteristics, leading to an elevated Fermi level (from −4.63 to −4.44 eV) and facilitating improved charge carrier extraction and transport in p‐i‐n perovskite devices. As a result, this strategy not only significantly enhances the power conversion efficiency (PCE) of the widely studied 1.55 eV bandgap perovskite but also boosts the PCE of 1.68 and 1.85 eV wide‐bandgap perovskite devices, achieving outstanding PCEs of 22.52% and 18.65%, respectively. These findings highlight the immense potential of TZC‐functionalized 1D perovskites for enhancing both high‐performance single‐junction perovskite and tandem solar cell applications.