Hybrid organic-inorganic photovoltaic junctions: case of the all thin-film CdSe/poly(3-methylthiophene) junction

The electrodeposition of poly-3(methylthiophene) (PMeT) on polycrystalline CdSe layers deposited by chemical bath deposition (CBD) on indium tin oxide (ITO) glass was rendered possible thanks to an electrochemical pretreatment consisting in polarizing the ITO surface at a potential lying in the underpotential region (upd region) of the Cd2+/Cd couple. The pretreatment is thought to cover the ITO surface with Cd adatoms which create nucleation centers for the growth of the CdSe layer, thus enhancing its adherence and permitting the PMeT electrochemical deposition without mechanical destruction of the CdSe film by the liquid electrolyte. The hybrid organic-inorganic CdSe/PMeT non-optimized junction so obtained exhibited a photovoltaic behaviour with an energy conversion efficiency, under 56 mW cm(-2) white light from a xenon lamp, of 1.3%, uncorrected for light losses by absorption when shined through pyrex glass/ITO bulk materials. (C) 1998 Elsevier Science B.V. All rights reserved.