Facile embedding of gold nanostructures in the hole transporting layer for efficient polymer solar cells

Photon harvesting by the active layers of bulk heterojunction (BHJ) polymer solar cells (PSCs) greatly influences the power conversion efficiency (PCE) of the devices. Inclusion of novel metal nanostructures in photoactive layers is one of the effective ways to enhance light trapping without increasing the device thickness. Here, we demonstrate a dramatic enhancement (up to 43%) of the power conversion efficiency (PCE) by exploiting gold nanostructures (AuNSs)-embedded graphene oxide (GO) as the hole transporting layer (HTL) in BHJ PSCs. The enhancement of the device performance could be attributed to the increase in both short circuit current density (J(sc)) and fill factor (FF). The increased FF is most likely the result of the enhanced charge collection through modified HTL and anode contact. Furthermore, the optical properties of the photovoltaic devices suggest that AuNSs cause light trapping via plasmonic effects resulting enhanced J(sc).