Tuning the size, concaveness, and aspect ratio of concave cubic gold nanoparticles produced with high reproducibility

• Published in: Materials today chemistry 2022-03, Vol.23, p.100657, Article 100657
• Main Authors: Singh, G., Agrawal, T., Lesani, P., Bisht, P.B., Zreiqat, H.
• Format: Article
• Language: English
• Subjects: Anisotropic nanoparticles; Concavity control; High indexed-facets; Localized surface plasmon resonance; Seed-mediated; Self-assembly
• ISSN: 2468-5194; 2468-5194
• DOI: 10.1016/j.mtchem.2021.100657

Reproducible fabrication of concave cubic gold nanoparticles with precise control over size, concaveness, and aspect ratio is important because the nanoscale structural characteristics can influence their plasmonic and catalytic properties. However, this is particularly challenging because the number of synthetic parameters involved in the fabrication strategy adds complexity to the reaction mechanism. Here, we introduce a simplified seed-mediated method and uncover the unknown conceptual insights on how the different halides and their concentration influence the surface structure and stability of underpotential silver monolayer deposited on the high energy facets of nanoparticles. The results reveal that adding Br− and I− ions to growth solution offers a predominant way to control the reaction kinetics and engineering nanoparticles with a predefined size, morphology, concaveness, aspect ratio, and plasmonic properties. Using spectroscopy and microscopy techniques, we shed new light on the reaction kinetics of concave cubic gold nanoparticles using the combined influence of silver underpotential deposition and halides. The strategy developed here can be expanded to fabricate gold nanoparticles of complex geometries. The results from our electromagnetic calculations suggest that the self-assembled superstructure of concave cubic gold nanoparticles can be more appealing for developing an ultra-sensitive sensing platform than to self-assembled superstructures of truncated cubic gold nanoparticles. [Display omitted] •A seed-mediated strategy for the first time is demonstrated to to grow gold nanoparticles with tunable concavity and size.•The study develops an intimate relationship between the structural characteristics of gold nanoparticles and growth parameters.•Changes in bromide ions concentration causes a morphological transformation from cubic to cuboid.•Self-assembled concave cubic gold nanoparticles show large enhancement in electric field than self-assembled cubic nanoparticles.