Enhanced localized surface plasmon resonance sensing on three-dimensional gold nanoparticles assemblies

Three-dimensional (3D) self-assemblies of metal nanoparticles (NPs) are attracting intense attention for sensing applications since they display unique optical properties which are distinct from their respective bulk and individual NP characteristics. In this paper, 3D self-assembled gold (Au) NPs multilayer structures have been fabricated by the alternate deposition of a bifunctional cross-linker and Au NPs, to improve the refractive index sensitivity of the localized surface plasmon resonance sensor. UV–vis spectroscopy, atomic force microscopy (AFM) and cross-section transmission electron microscopy (TEM) have been used to characterize the obtained multilayer structures. The investigations show that the number of Au NP deposition cycles has a strong effect on the sensitivity of the sensor and the multilayer structure fabricated from four NP deposition cycles exhibits maximum sensitivity to the change of the environmental refractive index.