Exploring the enhancement of infrared absorption through magnetically guided assembly of gold nanoparticle stabilized ferrofluid emulsion.

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

Abstract

The molecular vibration signals were amplified by the gold strip gratings as a result of grating resonances and nearby electric field hotspots. Colloidal gold island films exhibit similar enhancement; however, the uneven geometrical characteristics of these films restrict the tunability of the vibrational enhancement. Infrared absorption is enhanced by regular metallic patterns such as arrays of strips fabricated using a top-down approach such as nanolithography, although this technology is expensive and difficult. The significant infrared absorption may serve as tunable antenna sensitization to improve the sensor performance. In this article, we present a simple one-step process for fabricating optically sensitive ordered arrays of a gold nanoparticle ferrofluid emulsion in polyvinyl alcohol (PVA) using a magnetic field and spin-coating directed self-assembly (MDSCSA) process. Techniques such as UV-visible absorption, scanning electron microscopy, and Grazing-angle Infrared spectroscopy were used to evaluate various parameters associated with the nanostructures. Unlike the gold strips, the chain-like features in the iron oxide nanoparticle arrays were discontinuous. The fabricated chain-like ordered arrays have been shown to increase the local field to enhance the infrared absorption corresponding to the symmetric vibration of the-CH2 (2918cm-1) group present in PVA by ~667% at 45o grazing angle of, as the chain thickness (CT) increased by 178%. This scalable and simple method can potentially generate low-cost patterns for antenna sensitization.

Citation

OKPOZO, P., DWIVEDI, Y., HUO, D. and PANCHOLI, K. 2023. Exploring the enhancement of infrared absorption through magnetically guided assembly of gold nanoparticle stabilized ferrofluid emulsion. Hosted on OpenAIR [online]. Available from: https://rgu-repository.worktribe.com/output/1759908

• Working Paper Type: Working Paper
• 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
• Additional Information: This working paper was revised on 27 January 2023. It was previously titled "Magnetically directed self-assembled arrays of the gold nanoparticle stabilised Pickering ferrofluid emulsion for enhanced infrared absorption" when first deposited on 20 September 2022.