The use of a semiconducting polymer as a buffer layer replacement for CdS in traditionally all-inorganic copper-indium-gallium-diselenide (CIGS)-based solar cells is reported. The semiconducting polymer used is poly(benzimidazobenzophenanthroline) (BBL), which has physical and electronic properties that facilitate a suitable junction between the CIGS and the top electrode. We report on the fabrication, physical properties and photovoltaic characteristics of such Cd-free organic-inorganic devices, which have 6% power-conversion efficiencies. (C) 2007 Elsevier B.V. All rights reserved.