Photoinduced Conversion of Silver Nanospheres to Nanoprisms

TLDR

The study reports a photoinduced method that converts large quantities of silver nanospheres into triangular nanoprisms. The conversion was monitored by time‑dependent UV‑vis spectroscopy and TEM, revealing key intermediates, while theoretical calculations combined with experimental data assigned the nanoprism plasmon bands and identified two distinct quadrupole plasmon resonances. The resulting colloid displays distinctive optical properties—red scattering instead of the blue Rayleigh scattering of spheres—and the two quadrupole plasmon resonances, suggesting potential for multicolor diagnostic labels based on particle shape.

Abstract

A photoinduced method for converting large quantities of silver nanospheres into triangular nanoprisms is reported. The photo-process has been characterized by time-dependent ultraviolet-visible spectroscopy and transmission electron microscopy, allowing for the observation of several key intermediates in and characteristics of the conversion process. This light-driven process results in a colloid with distinctive optical properties that directly relate to the nanoprism shape of the particles. Theoretical calculations coupled with experimental observations allow for the assignment of the nanoprism plasmon bands and for the first identification of two distinct quadrupole plasmon resonances for a nanoparticle. Unlike the spherical particles they are derived from that Rayleigh light-scatter in the blue, these nanoprisms exhibit scattering in the red, which could be useful in developing multicolor diagnostic labels on the basis not only of nanoparticle composition and size but also of shape.