Liquid crystalline phthalocyanines in organic solar cells

Small exciton diffusion lengths, insufficient charge transport and low absorption prevent organic materials from achieving commercially useful power conversion efficiencies. The recently reported long exciton diffusion range along the columnar axes in the mesophase of disc shaped liquid crystals might represent a way to circumvent these limitations. In this paper we investigate a double-layer photovoltaic device comprising a discotic phthalocyanine derivative as electron-donor and a perylene derivative as electron-acceptor material. We fabricated one device with a pristine phthalocyanine layer and compare it with a device that was thermally treated to obtain a higher ordered mesophase.