UV-assisted flash light welding process to fabricate silver nanowire/graphene on a PET substrate for transparent electrodes

Graphene oxide and silver nanowires were bar coated onto PET substrates and then welded using an ultraviolet (UV)-assisted flash light irradiation process to achieve both high electrical conductivity and low haze. The irradiation process connected adjacent silver nanowires by welding, while simultaneously reducing the graphene oxide to graphene. This process was performed using a custom UV-assisted flash light welding system at room temperature under ambient conditions and was extremely rapid, with processing time of several milliseconds. The effects of varying the weight fractions of the silver nanowires and graphene oxide and of varying the UV-assisted flash light welding conditions (light energy and pulse duration) were investigated. The surface morphologies of the welded silver nanowire/graphene films were analyzed using scanning electron microscopy. Optical characterizations, including transmittance and haze measurements, were also conducted using a spectrophotometer. To test their resistance to oxidation, the welded silver nanowire/graphene films were subjected to high temperature in a furnace (100 °C), and their sheet resistances were measured every hour. The flash light welding process was found to yield silver nanowire/graphene films with high oxidation resistance, high conductivity (14.35 Ω·sq –1 ), high transmittance (93.46%), and low haze (0.9%). This material showed uniform temperature distribution when applied as a resistive heating film.