Enhancement of infrared absorption through a patterned thin film of magnetic field and spin-coating directed self-assembly of gold nanoparticle stabilised ferrofluid emulsion.

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

Abstract

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 tuneable 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-directed and spin-coating 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 (2918 cm−1) group present in PVA by ~667% at a 45° grazing angle, as the chain thickness (CT) increased by 178%. This scalable and simple method can potentially generate low-cost patterns for antenna sensitisation.

Citation

OKPOZO, P., DWIVEDI, Y., HUO, D. and PANCHOLI, K. 2023. Enhancement of infrared absorption through a patterned thin film of magnetic field and spin-coating directed self-assembly of gold nanoparticle stabilised ferrofluid emulsion. RSC advances [online], 13(34), pages 23955-23966. Available from: https://doi.org/10.1039/d3ra01369c

• Journal Article Type: Article
• Acceptance Date: Jul 29, 2023
• Online Publication Date: Aug 10, 2023
• Publication Date: Aug 10, 2023
• Deposit Date: Aug 11, 2023
• Publicly Available Date: Aug 24, 2023
• Journal: RSC advances
• Electronic ISSN: 2046-2069
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 34
• Pages: 23955-23966
• DOI: https://doi.org/10.1039/d3ra01369c
• Keywords: Optical sensing; Infrared absorption; Gold nanoparticles; Ferrofluid emulsions
• Public URL: https://rgu-repository.worktribe.com/output/2035578