Neutral-Color Semitransparent Organic Solar Cells with All-Graphene Electrodes

Graphene has been considered as a promising material for transparent electrodes due to its advantages including ultrahigh carrier mobilities, high optical transmittance, excellent mechanical flexibility, and good stability. Solar cells with all-graphene electrodes are potentially low-cost, high-performance, and environmental friendly, which however have not been realized until now. Here, we report the fabrication of semitransparent organic photovoltaics (OPVs) with graphene transparent electrodes as both cathode and anode, which can absorb light from both sides with the power conversion efficiency up to 3.4%. Meanwhile, the OPVs have a neutral color and show the transmittance of similar to 40% in the visible region, making them suitable for some special applications, such as power-generating windows and building integrated photovoltaics. This work demonstrates the great potential of graphene for the applications in carbon-based optoelectronic devices.