Akin, SeckinBauer, MichaelHertel, DirkMeerholz, KlausZakeeruddin, Shaik M.Graetzel, MichaelBaeuerle, Peter2024-02-222024-02-2220221616-301X1616-3028https://doi.org/10.1002/adfm.202205729https://hdl.handle.net/20.500.12452/10509Despite considerable development in performance, both poor operational stability and high costs associated with hole conductors such as 2,2 ',7,7 '-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9 '-spirobifluorene (spiro-OMeTAD) and Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA) of perovskite solar cells (PSCs) need to be addressed by the research community. Here, two nonspiro hole transporting materials (HTMs), namely HTM-1 and HTM-2, are designed and straightforwardly synthesized exhibiting remarkable electrochemical properties and hole mobilities. In particular, the PSC based on the methoxy derivative (HTM-2) exhibits a remarkable efficiency of 21.2% (stabilized efficiency of 20.8%), which is superior to the benchmark HTM spiro-OMeTAD (stabilized efficiency of 20.4%). These results establish that the molecular design is effective in improving the performance of PSCs. Importantly, these two HTMs show admissible long-term stability under different harsh conditions such as thermal stress up to 85 degrees C, high humidity level of 60% +/- 10%, and continuous illumination over 1000 h. These insights allow correlating the impact of molecular design on optoelectronic properties of nonspiro-based hole conductors with the overall device performance.eninfo:eu-repo/semantics/openAccessHole Transporting MaterialsLong-Term StabilityNonspiro Hole ConductorsPerovskite Solar CellsArticle32452-s2.0-85137339650Q1WOS:000849502500001Q110.1002/adfm.202205729