  Future wearable electronics, displays and photovoltaic devices rely on highly
conductive, transparent and yet mechanically flexible materials. Nowadays
indium tin oxide (ITO) is the most wide spread transparent conductor in
optoelectronic applications, however the mechanical rigidity of this material
limits its use for future flexible devices. Here we report novel transparent
conductors based on few layer graphene (FLG) intercalated with ferric chloride
(FeCl3) with an outstandingly high electrical conductivity and optical
transparency. We show that upon intercalation a record low sheet resistance of
8.8 Ohm/square is attained together with an optical transmittance higher than
84% in the visible range. These parameters outperform the best values of ITO
and of other carbon-based materials, making these novel transparent conductors
the best candidates for future flexible optoelectronics.
