Study of Arylamine-Substituted Porphyrins as Hole-Transporting Materials in High-Performance Perovskite Solar Cells

To develop new hole-transporting materials (HTMs) for efficient and stable perovskite solar cells (PSCs), 5,10,15,20-tetrakis­{4-[<i>N</i>,<i>N</i>-di­(4-methoxylphenyl)­amino-phenyl]}-porphyrin was prepared in gram scale through the direct condensation of pyrrole and 4-[bis­(4-methoxyphenyl)­amino]­benzaldehyde. Its Zn­(II) and Cu­(II) complexes exhibit excellent thermal and electrochemical stability, specifically a high hole mobility and very favorable energetics for hole extraction that render them a new class of HTMs in organometallic halide PSCs. As expected, <b>ZnP</b> as HTM in PSCs affords a competitive power conversion efficiency (PCE) of 17.78%, which is comparable to that of the most powerful HTM of Spiro-MeOTAD (18.59%) under the same working conditions. Meanwhile, the metal centers affect somewhat the photovoltaic performances that <b>CuP</b> as HTM produces a lower PCE of 15.36%. Notably, the PSCs employing <b>ZnP</b> show a much better stability than Spiro-OMeTAD. Moreover, the two porphyrin-based HTMs can be prepared from relatively cheap raw materials with a facile synthetic route. The results demonstrate that <b>ZnP</b> and <b>CuP</b> can be a new class of HTMs for efficient and stable PSCs. To the best of our knowledge, this is the best performance that porphyrin-based solar cells could show with PCE > 17%.