Formation of Monolayer Polystyrene Array Template for Gold Nanomesh Structure

Post-synthesis heating, a key step to tune the LPR band of gold nanorods covered with CTAB or embedded in a silica shell

“…Both solutions include a reductant, HAuCl 4 as gold source, and CTAB. In presence of CTAB, AuCl 4 − anions undergo metathesis reactions ultimately leading to the formation of AuBr 4 − , which can be observed by the passing from a yellow solution to an orange one [31]. In the first step (seed solution), the strong reducing agent, NaBH 4 reduces Au (III) to Au (0) in presence of CTAB that covers the spherical seeds to prevent them from coalescence high-quality seed solution is necessary to obtain high-quality nanorods.…”

“…Since their first discovery in 1991, for their wide perspective of applications, many synthetic protocols have been developed with the aim of improving the control over the yield of the synthesis, the uniformity in shape and dimension, but in particular on the most tricky part: the precise control of aspect ratio (the ratio between the length and the diameter), which mostly determines the features (shift and width) of the longitudinal band [28,29]. To date, the most effective way to control the shape of AuNRs has been achieved using the seeded growth method [30][31][32]. The basic principle of this shape-controlled method involves two steps: first, the preparation of small-size spherical AuNPs, and second, the growth of the prepared spherical particle in a rod-like micelle environment.…”