Simple brush painted Ag nanowire network on graphene sheets for flexible organic solar cells

The authors report on highly flexible and transparent Ag nanowire (NW) coated graphene hybrid electrodes for flexible organic solar cells (FOSCs). Brush painted Ag NW percolating network on the transparent graphene sheet led to an invisible Ag NW/graphene hybrid electrode with a sheet resistance of 15.25 Ω/sq. and a high optical transmittance of 77.4% as well as superior flexibility. In particular, similar bending radius of Ag NW/graphene hybrid electrode to graphene bilayer electrode during outer bending test demonstrated the superior mechanical flexibility of the Ag NW/graphene hybrid electrodes. FOSCs fabricated on Ag NW/graphene hybrid electrode showed higher power conversion efficiency (2.681%) than that (1.681%) of FOSC with graphene bilayer electrode due to lower sheet resistance and improved wettability for hole extracting layer. This indicates that brush painting of conductive Ag NW is a critical solution to solve the problem of high resistance and hydrophobic graphene electrode for use in FOSC.