Organic photovoltaic devices based on graphene as an electron-acceptor material and P3OT as a donor material

We present the fabrication and performance studies of organic photovoltaic (OPV) devices with bulk heterojunction (BHJ) structure that use organic solution-processable functionalized graphene (SPFGraphene) as an electron-acceptor material and poly(3-octylthiophene) (P3OT) as a donor material. The structural configuration of the device is ITO/PEDOT:PSS/P3OT:PCBM–SPFGraphene/LiF/Al. After mixing graphene into the device, the performance enhanced significantly. Given illumination at 100 mW/cm2 AM1.5 and P3OT/PCBM (1:1) mixture with 9 wt% of SPFGraphene, we recorded the best performances. The open-circuit voltage (Voc) is 0.67 V. The short-circuit current density (Jsc) is 4.6 mA/cm2. The FF is 0.37. And the power conversion efficiency is 1.14%. In the P3OT:PCBM–SPFGraphene composite, the SPFGraphene acts as exciton dissociation sites and provides the transport pathway of LUMO–graphene–Al. Adding SPFGraphene into P3OT produces an appropriate energetic distance between the HOMO and the LUMO of the donor/acceptor, which leads to a high open-circuit voltage. Besides, doping SPFGraphene provides a higher exciton dissociation volume mobility of carrier transport, which leads to a large short-circuit current density.