Photovoltaics based on thin electrodeposited bilayers of poly(3-methylthiophene) and polypyrrole

We investigate photovoltaic devices whose active layers are composed by bilayers formed with poly(3-methylthiophene) (PMeT) and polypyrrole (PPy), in different stacking sequences. The polymer films in these devices are electrochemically deposited, using glass covered with tin-oxide as substrate. Aluminum is used as top electrode. PMeT and PPy films present different surface roughness, so that in bilayer devices the roughness of the interface between both polymers is dependent on stacking sequence as well as on layer thickness. As a consequence, device performance also depends on polymer stacking sequence and polymer layers thickness. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.