Highly Sensitive Local Surface Plasmon Resonance in Anisotropic Au Nanoparticles Deposited on Nanofibers

This paper reports the facile and high-throughput fabrication method of anisotropic Au nanoparticles with a highly sensitive local surface plasmon resonance (LPR) using cylindrical nanofibers as substrates. The substrates consisting of nanofibers were prepared by the electrospinning of poly(vinylidene fluoride) (PVDF). The Au nanoparticles were deposited on the surface of electrospun nanofibers by vacuum evaporation. Scanning electron microscopy revealed the formation of a curved Au island structure on the surface of cylindrical nanofibers. Polarized UV-visible extinction spectroscopy showed anisotropy in their LPR arising from the high surface curvature of the nanofiber. The LPR of the Au nanoparticles on the thinnest nanofiber with a diameter of ~100 nm showed maximum refractive index (RI) sensitivity over 500 nm/RI unit (RIU). The close correlation between the fiber diameter dependence of the RI sensitivity and polarization dependence of the LPR suggests that anisotropic Au nanoparticles improve RI sensitivity.