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

Abstract

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.