Environmental and economic assessment of ITO-free electrodes for organic solar cells

The use of Indium-Tin Oxide (ITO) as a transparent conductor in organic photovoltaic (OPV) devices has been shown to present a bottleneck for the technology due to the use of the rare metal Indium and also the energy intensive manufacturing processes required and subsequent high economic cost. This study discusses some of the alternative materials, which are being considered for use as transparent conductors in OPV modules. A life cycle and cost analysis of a number of the most promising ITO-free transparent conductors, namely: high conductivity PEDOT:PSS; a silver grid embedded in PEDOT:PSS; silver nanowires; single walled carbon nanotubes are completed in this study. The results show that there is great potential for reducing both the energy pay-back time and the cost of OPV modules by replacing ITO with an alternative transparent conductor. (C) 2011 Elsevier B.V. All rights reserved.