Columnar Structure in Bulk Heterojunction in Solution-Processable Three-Layered p-i-n Organic Photovoltaic Devices Using Tetrabenzoporphyrin Precursor and Silylmethyl[60]fullerene

A new solution-processable fabrication protocol using a soluble tetrabenzoporphyrin (BP) precursor and bis(dimethylphenylsilylmethyl)[60]fullerene (SIMEF) created three-layered p-i-n photovoltaic devices, in which the i-layer possesses a well-defined bulk heterojunction structure in which columnar BP crystals grow vertically from the bottom p-layer. The device showed a power conversion efficiency of 5.2% (V-oc = 0.75 V; J(sc) 10.5 mA/cm(2); FF = 0.65).