Single heterojunction and multi-heterojunction, small-molecule organic photovoltaic devices (OPVs) have been prepared on Glass/ITO and fully-flexible thermoplastic substrates using pre-patterned, conducting polymer electrodes (~ 450Ω/□). OPVs were fabricated via sequential vacuum vapor deposition of layers of the organic
electron donating/hole transporting material: N,N'-(a-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (a-NPD) and the electron accepting/transporting material C60. Devices built on glass/ITO substrates operated with a maximum, white-light power conversion efficiency (ηpower) of 1.1% (AM1.5, 97 mW/cm2). Analogous devices fabricated on fully-flexible, plastic substrates using conducting polymer transparent electrodes exhibited white-light power conversion efficiencies of ~1%, virtually identical to those fabricated on prepatterned ITO/glass
substrates. The glass/ITO cells were further optimized by including an exciton blocking layer of 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and their ηpowerS exhibited a 30% increase to 1.3%.