Continuous flow synthesis of plasmonic gold patches and nearly-complete nanoshells on polystyrene core particles (Open Access)--颗粒学报PARTICUOLOGY

Meincke, T., & Klupp Taylor, R. N. (2023). Continuous flow synthesis of plasmonic gold patches and nearly-complete nanoshells on polystyrene core particles. Particuology, 75, 137-150. https://doi.org/10.1016/j.partic.2022.06.007

Continuous flow synthesis of plasmonic gold patches and nearly-complete nanoshells on polystyrene core particles (Open Access)

Thomas Meincke ^a, Robin N. Klupp Taylor^{a b *}

a Institute of Particle Technology, Friedrich-Alexander University Erlangen-Nürnberg, Cauerstrasse 4, 91058, Erlangen, Germany
b Collaborative Research Center 1411 - Design of Particulate Products, Friedrich-Alexander University Erlangen-Nürnberg, Cauerstrasse 3, 91058, Erlangen, Germany

10.1016/j.partic.2022.06.007

Volume 75, April 2023, Pages 137-150

Received 24 May 2022, Revised 30 June 2022, Accepted 30 June 2022, Available online 6 August 2022, Version of Record 19 August 2022.

E-mail: robin.klupp.taylor@fau.de

Highlights

• Gold patches formed on polystyrene spheres by heterogeneous nucleation and growth.

• Millimetre-scale T-mixer process results in better product uniformity than batch process.

• Patch morphology tuned from dendritic to conical by adjusting reaction conditions.

• Tunable optical properties were due to localized surface plasmon resonances of the patches.

• Setup extended with a second T-mixer to produce nearly-complete gold nanoshells.

Abstract

We describe the development of a T-mixer based continuous flow process for the coating of 86–500 nm diameter spherical polystyrene particles with thin gold patches by heterogeneous nucleation and growth. After establishing a suitable flow rate for good mixing and sufficiently uniform product morphology we systematically investigate the main reaction parameters. This reveals a considerable tunability of the patch morphology and, by virtue of the localized surface plasmon resonance of gold, the optical properties of the product dispersions. In order to further widen the range of nanostructures accessible by our process, a second T-mixer was added. This introduced new gold precursor, leading to further growth of the patches that were formed after the first mixer. By this approach, nearly-complete gold nanoshells could be produced in high yield on both small and large core particles, without the unwanted production of free-standing gold nanoparticles. Due to the pronounced optical properties of nearly-complete gold nanoshells on small core particles, we could estimate from electrodynamic simulations the equivalent shell thickness to be as low as 8.6 nm. This is significantly thinner than can be routinely achieved using the standard seeded growth approach to synthesise gold nanoshells. Our results are therefore highly promising for the gram-scale synthesis of plasmon resonant nanostructures with designed optical properties.

Graphical abstract

Keywords

Continuous flow; Core-shell particles; Patchy particles; Nucleation; Diffusion limited growth

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