Photovoltaic properties of a photovoltaic cell with structure indium-tin oxide (ITO)/ZnO/C-60/POly(3-hexylthiophene) (PAT6)/Au have been investigated. The C-60/PAT6 heterojunction of this cell was fabricated by spin-coating a chloroform solution of PAT6 onto the C-60 thin film formed on ZnO-coated ITO. Fabricated by this method, the photovoltaic cell has demonstrated a high efficiency for solar cells based on organic polymers, i.e. a monochromic external quantum efficiency of over 70% at the peak wavelength and a power conversion efficiency of 1.0% under AM1.5 spectral illumination of 100 mW cm(-2).