Synthesis of a Fully Conjugated Phthalocyanine‐Diketopyrrolopyrrole‐Phthalocyanine Triad as Low Band Gap Donor in Small Molecule Bulk Heterojunction Solar Cells

Abstract

We describe the synthesis and photovoltaic properties of a fully conjugated phthalocyanine‐diketopyrrolopyrrole‐phthalocyanine triad (ZnPc‐DPP‐ZnPc) that presents strong visible absorption from 400 to 900 nm. The synthesis of the phthalocyanine with full conjugation to diketopyrrolopyrrole provides access to a new family of low band gap materials (<1.6 eV). Organic solar cells employing bulk heterojunction ZnPc‐DPP‐ZnPc:PC 70 BM films using MoO 3 as anodic interfacial layer (IFL) show a power conversion efficiency of 1.04 %. The power conversion efficiency decreases considerably by using PEDOT:PSS as interfacial layer as a consequence of protonation of the ZnPc.