Influence of nonionic surfactant-modified PEDOT:PSS on graphene

Graphene is a potential candidate for use as the transparent conducting electrode in organic photovoltaics and is emerging as a possible substitute for conventional indium tin oxide-based electrodes. However, challenges such as difficulty in coating other materials on top of graphene and stable doping of graphene have yet to be overcome to improve device performance. Here, we have developed a simple approach to improve the wettability of poly(3,4-ethylene-dioxy-thiophene):poly-(styrenesulfonate) (PEDOT:PSS) polymer on a graphene surface by mixing it with a nonionic small molecule surfactant (Triton X-100). This results in a uniform coating over the graphene surface and simultaneously increases the conductivity via doping effects. The significance of this strategy has been verified in organic photovoltaics on flexible substrates. These photovoltaics on flexible substrate show maximum power conversion efficiency (PCE) values of 3.19%, which are much improved compared to photovoltaics with pristine graphene electrodes (1.12%).