Zn(II) and Cu(II) tetrakis(diarylamine)phthalocyanines as hole-transporting materials for perovskite solar cells

Finding new hole-transporting materials (HTMs) suitable for replacing the state-of-the-art spiro-OMeTAD is still challenging. In this work, newly synthesized diarylamine-substituted metal phthalocyanines (MPcs, M = Zn(II) or Cu(II)) functionalized with either linear or branched alkoxy chains are evaluated as HTMs in perovskite solar cells. Both the nature of the alkoxy chains and that of the coordinated metal species were found to influence the functional properties of the new MPcs. In particular, devices based on a ZnPc featuring four n-butoxy side chains exhibited the highest power conversion efficiencies (PCEs). A PCE of 20.00% was reached for triple cation perovskite devices, and a PCE up to 20.18% could be achieved for double cation devices.