Synthesis of an octathienyl-fused phthalocyanine as a donor material for organic solar cells

We report the synthesis and properties of a phthalocyanine derivative with eight fused thienyl rings and eight triisopropylsilylethynyl substituents. The fused thienyl rings were designed to enhance intermolecular interactions among the phthalocyanine molecules in the solid state whereas the triisopropylsilylethynyl substituents were aimed to improve solubility. Compared to the simple octa(2-thienyl) substituted phthalocyanine, a remarkable decrease of solubility and a 67 nm red shift in UV-visible absorption maximum were observed. The fused thienyl compound was used as a donor material in bulk heterojunction solar cells. The power conversion efficiency of 0.60% was achieved under simulated solar illumination.