Silver Nanowires Deposited on Cellulose Nanofibers/Graphene Oxide Hybrid Membranes as Sandwich-Structured Films for Optoelectronic and SERS Applications

Flexible conductive films with high surface conductivity, broadband optical absorption, and excellent chemical and thermal stabilities are desired for optoelectronic applications. Herein, a facile layer-by-layer vacuum filtration method is presented to fabricate a sandwich-structured conductive film with silver nanowires (AgNWs) that adhere to the surface of cellulose nanofibers (CNF)/graphene oxide (GO) hybrid membranes. The middle CNF/GO layer offers a flexible and stable substrate for the AgNWs layer to form a condensed stratiform structure. The well-designed sandwich-structured film exhibited conductive anisotropy with improved conductivity along the in-plane direction and insulating properties along the cross-plane direction. The successful coating of monatomic GO sheets on AgNWs network resulted in a sheet resistance lower than 7 Ω sq–1 due to the reduction of the contact resistance between the AgNWs junctions. Thanks to the synergistic effect between the CNF/GO substrate and the AgNWs layer which with excellent localized surface plasmonic property, the sandwich-structured film not only achieved efficient broadband optical absorption up to ∼80% at visible and near-infrared frequencies but also demonstrated prominent surface-enhanced Raman scattering (SERS) performance. Moreover, the film exhibited outstanding mechanical durability, including thermal and chemical stability, demonstrably resisting high temperature and solvent corrosion in harsh environments, making it suitable for promising applications in flexible optoelectronic devices.