Preparation of saline-stable, silica-coated triangular silver nanoplates of use for optical sensing.

Triangular silver nanoplates (TSNPs) may find application in next generation optical bio-sensors owing to the high sensitivity of the spectral position of their main plasmon band to changes in local refractive index. Unfortunately, etching of the anisotropic nanoplates to spherical particles occurs upon exposure to chloride ions from salt, with a concomitant decrease in optical sensitivity. Herein are detailed two general methods for the silica coating of TSNPs, with the aim of forming a protective barrier against chloride etching.

Versatile solution phase triangular silver nanoplates for highly sensitive plasmon resonance sensing.

Solution phase triangular silver nanoplates (TSNP) with versatile tunability throughout the visible-NIR wavelengths are presented as highly sensitive localized surface plasmon refractive index sensors. A range of 20 TSNP solutions with edge lengths ranging from 11 to 200 nm and aspect ratios from 2 to 13 have been studied comprehensively using AFM, TEM, and UV-vis-NIR spectroscopy. Studies of the localized surface plasmon resonance (LSPR) peak's sensitivity to refractive index changes are performed using a simple sucrose concentration method whereby the surrounding refractive index can solely be changed without variation in any other parameter.