Uniform Deposition of Silver Nanowires and Graphene Oxide by Superhydrophilicity for Transparent Conductive Films

Superhydrophilic surfaces were used to achieve a uniform deposition of one-dimensional (1D) and two-dimensional (2D) nanomaterials for high performance transparent conductive films. Suspensions of silver nanowires (AgNWs, 1D) and graphene oxide (GO, 2D) were deposited on pristine glass substrates and superhydrophilic surfaces through various deposition methods. It was discovered that the coffee-ring effect, often observed during drop-casting, was suppressed by the rapid wetting of suspensions into a thin liquid sheet on superhydrophilic surfaces. Drop-casting of AgNW suspensions on superhydrophilic surfaces produced a uniform AgNW network that provided low sheet resistance (Rs) and high percent transmittance (%T) at 550 nm. The sample of a Rs of 250 Ω sq–1 had a %T of 97.7, and the sample of a Rs of 24.7 Ω sq–1 had a greater %T than pristine glass. Spray-coating of GO suspensions onto superhydrophilic films coated with AgNWs generated a conformal coating that reduced the areal root-mean-square roughness (Sq) from 28.4 nm down to 15.7 nm but showed limited improvement to the conductivity of the network. Conformal Au coating of the AgNW network stabilized the film against oxidation and granted mechanical stability through subsequent aqueous processing, such as spray-coating of GO films. The superhydrophilic substrates with antireflective properties were successful in generating high-performance TCFs and allowed for study of the dynamic processes of film formation from liquid dispersions of nanomaterials.