Photoinduced conversion of silver nanospheres to nanoprisms

A photoinduced method for converting large quantities of silver nanospheres into triangular nanoprisms is reported. The photo-process has been charact erized by time-dependent ultraviolet-visible spectroscopy and transmission electron microscopy, allowing for the observation of several key intermedia tes in and characteristics of the conversion process. This light-driven pro cess results in a colloid with distinctive optical properties that directly relate to the nanoprism shape of the particles. Theoretical calculations c oupled with experimental observations allow for the assignment of the nanop rism plasmon bands and for the first identification of two distinct quadrup ole plasmon resonances for a nanoparticle. Unlike the spherical particles t hey are derived from that Rayleigh tight-scatter in the blue, these nanopri sms exhibit scattering in the red, which could be useful in developing mult icolor diagnostic labels on the basis not only of nanoparticle composition and size but also of shape.