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Magnetically directed self-assembled arrays of the gold nanoparticle stabilised Pickering ferrofluid emulsion for enhanced infrared absorption.

Okpozo, Paul; Dwivedi, Yashashchandra; Huo, Dehong; Pancholi, Ketan

Authors

Yashashchandra Dwivedi

Dehong Huo



Abstract

Gold strip gratings enhance the molecular vibration signals, due to grating resonances and local electric field hot spots. Such enhancement is also observed in colloidal gold island films; however, the random geometrical features of these films tend to provide nonlinear relation of enhancement with morphological features, leading to limit on tunability. Fabrication of well-defined metal patterns using a top-down approach such as nanolithography provides a tuneable antenna to enhance the absorption, although this technique is costlier and complex. To simplify the process, a magnetic and spin coating-directed self-assembly (MSCDS) was used to prepare optically-sensitive ordered arrays of the gold nanoparticle Pickering ferrofluid emulsion chains in polyvinyl alcohol (PVA) on glass substrate. Unlike gold strips, the chains in arrays were discontinuous, contained iron oxide nanoparticles (NP) and contributed to nonlinear enhancement. Despite these shortcomings, the chain-like ordered arrays have shown to increase local field to enhance the infrared absorption corresponding to asymmetric vibration of -CH2 (2920cm-1) bond present in PVA by 40% at 45 degrees grazing angle, as chain thickness (CT) increased by 178%. This scalable and simple method has potential to generate patterns for absorbing antennas.

Citation

OKPOZO, P., DWIVEDI, Y., HUO, D. and PANCHOLI, K. 2022. Magnetically directed self-assembled arrays of the gold nanoparticle stabilised Pickering ferrofluid emulsion for enhanced infrared absorption. Hosted on OpenAIR [online]. Available from: https://rgu-repository.worktribe.com/output/1759908

Deposit Date Sep 29, 2022
Publicly Available Date Sep 29, 2022
Publisher Wiley
Keywords Nanofabrication; Magnetism; Thin films; Antennas
Public URL https://rgu-repository.worktribe.com/output/1759908

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