Gold nanoparticles (AuNPs) with their unique surface plasmon resonance (SPR) properties have been widely applied in enhanced spectroscopies, biosensors, photothermal therapy, and solar light harvesting. The SPR properties of AuNPs are highly dependent on the particle size and shape. It has been shown that AuNPs can be oxidized by Au(III) in the presence of cetyltrimethylammonium bromide (CTAB) due to the strong binding between them. Oxidation occurs preferentially at the surface sites with higher curvatures, leading to transformation of gold nanoprisms to gold nanodisks. Here, we report that when the CTAB is replaced by cetyltrimethylammonium chloride (CTAC), a unique reshaping behavior is observed. The gold nanoprisms first undergo conventional etching of the tips of the gold nanoprisms (~60 nm edge length), leading to the shift of plasmon peak from 648 nm to 556 nm. However, after a certain period of time, the shape of gold nanoprisims is recovered, accompanied with plasmon peak shifting back to 632 nm. High-resolution transmission electron microscopy (TEM) and selected area diffraction (SAED) images at different stages indicate the crystallinity of gold is preserved. Preliminary in-situ UV-vis spectroscopy study suggests redeposition of gold atoms on gold nanoprisms, leading to recovery of the shape. More detailed study of the reshaping mechanism is ongoing.

Unique reshaping behavior of gold nanoprisms in the presence of cetyltrimethylammonium chloride

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.