Growing In-Plane Multiplex Plasmonic Arrays for Synergistic Enhanced Photocurrent Response

A complete control of the localized surface plasmon resonance (LSPR) properties of different types of metal nanoparticles (size, shape, or composition) in a device by facile techniques with high throughput is crucial to intensively study and apply the LSPR effects to improve device performance. Here, a versatile approach is presented to fabricate macroscopic and in-plane multiplex arrays of plasmonic nanoparticles with well-defined particle size or composition allocation. The polymer layer (poly(N-isopropylacrylamide), PNIPAM) spin-coated on the surface of the substrate is applied as a protective layer to control the growth of the Au nanoparticles in a dip-coating procedure. The relative contribution of LSPR of each particle type can be controlled by selectively adjusting the particle size or composition at the desired position of multiplex arrays on the same substrate. A synergistic enhanced photocurrent response is observed in the metal–semiconductor system, which is attributed to broadened LSPR enhancement of multiplex composition (Au and Au@Ag) structures from the same substrate. The fabrication procedure presented in this study is highly repeatable and feasible for preparing ordered multiplex nanostructures on the same substrate. Furthermore, this method provides a cost-effective and versatile platform for design of multiplex plasmonic nanostructures in sensing, solar energy conversion, and optical processing applications.