Search

In the pursuit of highly efficient perovskite solar cells, spiro‐OMeTAD has demonstrated recorded power conversion efficiencies (PCEs), however, the stability issue remains one of the bottlenecks constraining its commercial development. In this study, we successfully synthesize a novel self‐polymerized spiro‐type interfacial molecule, termed v‐spiro. The linearly arranged molecule exhibits stronger intermolecular interactions and higher intrinsic hole mobility compared to spiro‐OMeTAD. Importantly, the vinyl groups in v‐spiro enable in situ polymerization, forming a polymeric protective layer on the perovskite film surface, which proves highly effective in suppressing moisture degradation and ion migration. Utilizing these advantages, poly‐v‐spiro‐based device achieves an outstanding efficiency of 24.54 %, with an enhanced open‐circuit voltage of 1.173 V and a fill factor of 81.11 %, owing to the reduced defect density, energy level alignment and efficient interfacial hole extraction. Furthermore, the operational stability of unencapsulated devices is significantly enhanced, maintaining initial efficiencies above 90 % even after 2000 hours under approximately 60 % humidity or 1250 hours under continuous AM 1.5G sunlight exposure. This work presents a comprehensive approach to achieving both high efficiency and long‐term stability in PSCs through innovative interfacial design. [ABSTRACT FROM AUTHOR]

In traditional n‐i‐p‐type perovskite solar cells (PSCs), most hole transporting materials (HTMs) rely on an uncontrolled oxidative process using Li salt and Co (III) complex to achieve sufficient hole mobilities. Herein, a stabilized oxidized phenothiazine‐based HTM (OPTZ) synthesized from its neutral form (NPTZ) through a photoredox reaction is demonstrated. This controllable and stable oxidation state is mainly derived from the planar structure and π conjugation of phenothiazine core in OPTZ. The energy gap between the singly occupied molecular orbital (SOMO) of OPTZ and highest occupied molecular orbital (HOMO) of NPTZ suitably promotes hole hopping in hole transporting layers. Using an optimized ratio of OPTZ as the dopant in NPTZ, the hole transporting mobility is effectively enhanced due to an intra‐ and intermolecular charge transfer process, resulting in an enhancement in the fill factor of the PSCs. Herein, a new strategy to obtain stabilized oxidized HTMs, which deliver significantly enhanced hole mobilities of HTMs in PSCs, is provided. [ABSTRACT FROM AUTHOR]