A localized surface plasmon resonance nanosensor based on rhombic Ag nanoparticle array

A localized surface plasmon resonance (LSPR) nanosensor by using a rhombic Ag nanoparticle array is proposed and developed. The LSPR extinction spectra of the antigen or antibody with lower concentration are detected. The obtained results detected from 100 nM target molecule indicate a larger wavelength shift for the rhombic based nanosensor than the triangular based nanosensor. By experimental detection, we demonstrated that the refractive index sensitivity is 266.2 nm per refractive index unit for Ag rhombic nanoparticle with in-plane width of ∼140 nm and out-of-plane height of 47 nm.