Ordering silver nanowires for chiroptical activity

Abstract

With the development of chiral materials, remarkable progress has been made in the application fields of biology, chemistry, and physics in the past decades. Here we develop a solo-Ag-nanowire (NW)-based, bottom-up chiral construction strategy to fabricate a chiral plasmonic film with strong chiroptical activity in the purple-blue band. Finite-difference time-domain simulations predict that helical structures made by Ag NWs with certain interlayer angles possess strong chiroptical intensity. We then apply a Langmuir-Blodgett technique to construct the layered NW assemblies with both handedness via regulating interlayer angle direction. The Ag NW assemblies show the interlayer-angle-and film-thickness-dependent circular dichroism, reaching the highest anisotropic factor of 0.03. These new chiral structures will serve as ideal candidates for chiral sensors thanks to their specific plasmonic properties.