Immobilization of gold nanoparticles on silanized substrate for sensors based on localized surface plasmon resonance

We propose a detailed method of preparing immobilized gold nanoparticles on a substrate for application to dielectric sensors. We show the relationship between the amount of aminofunctional silane on the substrate and the absorbance caused by localized surface plasmon resonance of the gold nanoparticles. The amount of silane was changed by controlling rinsing time with distilled water. In the rinsing process, two features of dispersion for isolated nanoparticles on the substrate were observed. One was a high density of nanoparticles, but with some of them incompletely isolated; the other was a low density of nanoparticles, but all completely isolated. To confirm the suitability for sensor applications, we measured the absorption spectra of the substrates surrounding media of various dielectric constants.