Improvement of conductivity of graphene-silver nanowire hybrid through nitrogen doping using low power plasma treatment

Graphene-silver nanowire (AgNW) hybrid structure is a potential candidate to replace indium tin oxide (ITO) owing to its high conductivity, transparency, and flexibility. The thin insulating polyvinylpyrrolidone (PVP) residual surfactant coating that forms on AgNW weakens the wire-to-wire and wire-to-graphene contact, resulting in a higher sheet resistance. For this reason, a post-processing treatment such as high-temperature annealing is usually carried out to reduce the sheet resistance. In this paper, low power nitrogen plasma is utilized to increase the electrical conductivity of the hybrid through the partial removal of PVP and simultaneous doping of graphene without employing any high-temperature annealing treatment. A reduction of over 34% in sheet resistance is obtained for the hybrid compared with a 17% reduction for the AgNW electrode alone. The hybrid electrode, in comparison to the AgNW electrode alone, results in an electrical to optical conductivity ratio (σ_DC/σ_OP) of 234 in 45 s without losing its transparency. In comparison to the 4% reduction of sheet resistance caused by high temperature annealing at 180 °C for 30 min, nitrogen plasma treatment results in a substantially higher reduction (>34%) of the sheet resistance of hybrids in a substantially shorter processing time (45 s).