A flexible conductive film prepared by the oriented stacking of Ag and Au/Ag alloy nanoplates and its chemically roughened surface for explosive SERS detection and cell adhesion

A large-scale assembly of nanostructured building blocks into bulk flexible film with multifunctional applications is the key point in colloidal nanomaterials research. In this study, a centimeter-scale flexible conductive film was prepared by the oriented stacking of Ag nanoplates on a polyethylene glycol terephthalate (PET) flexible substrate and it displayed an ideal ohmic contact and low resistance (112 Ω cm^-1). Via a solid-liquid interface galvanic replacement reaction with HAuCl₄, a Au-Ag alloy nanoplate film was obtained with an enhanced conductivity (10.2 Ω cm^-1) and controllable surface roughness. The optimized surface roughness of this flexible conductive film enabled the ultrasensitive surface-enhanced Raman spectroscopy (SERS) detection of explosives (TNT and RDX) and their differentiation at low concentrations (10 nM). Moreover, the synergistic nanoscale and microscale surface roughness of this Au-Ag alloy nanoplate film endowed good biocompatibility and demonstrated applicable biological cell adhesion performance.