Visibly-Transparent Organic Solar Cells on Flexible Substrates with All-Graphene Electrodes

Portable electronic devices have become increasingly widespread. Because these devices cannot always be tethered to a central grid, powering them will require low-cost energy harvesting technologies. As a response to this anticipated demand, this study demonstrates transparent organic solar cells fabricated on flexible substrates, including plastic and paper, using graphene as both the anode and cathode. Optical transmittance of up to 69% at 550nm is achieved by combining the highly transparent graphene electrodes with organic polymers that primarily absorb in the near-IR and near-UV regimes. To address the challenge of transferring graphene onto organic layers as the top electrode, this study develops a room temperature dry-transfer technique using ethylene-vinyl-acetate as an adhesion-promoting interlayer. The power conversion efficiency achieved for flexible devices with graphene anode and cathode devices is 2.8%-3.8% at for optical transmittance of 54%-61% across the visible regime. These results demonstrate the versatility of graphene in optoelectronic applications and it is important step toward developing a practical power source for distributed wireless electrical systems.