Inverted Polymer Solar Cells with a Reduced Graphene Oxide/Poly (3,4-Ethylene Dioxythiophene):Poly(4-Styrene Sulfonate) (PEDOT:PSS) Hole Transport Layer

Abstract

In this study, high-efficiency inverted polymer solar cells were developed by using graphene oxide/poly(3,4-ethylene-dioxythiophene):poly(4-styrene-sulfonate) (GO/PEDOT:PSS) composites films acting as hole transport layer into the device structure based on Indium Tin Oxide (ITO)/Zinc Oxide (ZnO)/Poly(3-hexylthiophene):[6,6]phenyl-C61-butyric Acid Methyl Ester (P3HT:PCBM)/GO:PEDOT:PSS/Silver (Ag). The electrical conductivity and Seebeck coefficient of the films have been measured at room temperature and a maximum of conductivity achieved was for 492 S/cm for a 3 wt.% GO/PEDOT:PSS film treated with dimethyl sulfoxide as solvent and a decrease in the conductivity was observed for higher content of GO even after chemical or thermal reduction. The energy conversion efficiency was enhanced from 2.14% to 3.06% by incorporating 3 wt.% of GO into the PEDOT:PSS buffer layer. Thus, the 3 wt.% GO/PEDOT:PSS is a promising buffer layer for photovoltaic and electronic applications, since a decrease of the overall performance of the photovoltaic device was observed for higher concentration of GO.