Experimental and theoretical studies of Surface Acoustic Wave enhanced Localised Surface Plasmon Resonance sensors

Sindal, Chandresh (2025) Experimental and theoretical studies of Surface Acoustic Wave enhanced Localised Surface Plasmon Resonance sensors. PhD thesis, University of Glasgow.

Abstract

Integrating different sensing platforms offers several advantages, such as enhanced sensitivity and advanced sensing mechanisms. Surface acoustic wave (SAW) devices have been used for microparticle manipulation for a long time, offering precise and controlled manipulation in a contactless manner. Similarly, localised surface plasmon resonance (LSPR) sensors also offer a label-free sensing platform without engagement of any human contact. LSPR is an extremely sensitive sensing mechanism which can sense a small change in the NPs' dimensions and the surrounding medium. On the other hand, SAW devices offer several approaches for particle manipulation such as mixing, separation and patterning, so SAW can be used for sample preparation, transport and deliver it to the desired location. Integration of the SAW with LSPR offers to development of a complete sensing setup where SAW can be used to manipulate plasmonic particles and LSPR can be utilised for their ultra-sensing capabilities.

This thesis presents a novel approach for integrating SAW devices with LSPR sensing, based on the manipulation of a plasmonic monolayer. For the integration of the SAW with LSPR sensing, a stable and detectable plasmonic particle structure is necessary. A two-dimensional layer of plasmonic nanoparticles offers a key benefit in such configurations where the dimensions of self-assembled particles are comparable to the SAW wavelength, and yet the plasmonic properties remain preserved, essential for an LSPR sensor. Before the integration, we confirmed that the effects of SAW propagation, which generate spontaneous surface deformation, do not alter the plasmonic properties that can affect the resonance spectrum, implying that the LSPR properties remain unchanged.

Theoretically and experimentally, we confirmed that the shear vertical-SAW (SV-SAW) cannot affect the LSPR spectrum of gold nanoparticles. Eventually, we prepared the gold nanoparticle monolayer and used it with the SAW device for the alignment and patterning. The most significant advantage of our novel work is that the pattern remains intact when SAW is off, and even when the microchannels are removed. The experimental SAW setup allowed refractive index (RI) sensing by integrating it with the LSPR setup. To the best of our knowledge, this was the first demonstration that SV-SAW propagation cannot affect the plasmonic structure over the surface of the SAW device and is able to manipulate micro structured metallic monolayers in a contactless manner.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Due to copyright issues, this thesis is not available for viewing. Supported by funding from Department of Social Justice and Empowerment, Ministry of Social Justice and Empowerment, Government of India, for the National Overseas Scholarship Program (NOS)
• Subjects: T Technology > T Technology (General)
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Funder's Name: Government of India, National Overseas Scholarship Program (NOS)
• Supervisor's Name: Cooper, Professor Jonathan M. and Reboud, Professor Julien
• Date of Award: 2025
• Depositing User: Theses Team
• Unique ID: glathesis:2025-85474
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 26 Sep 2025 08:29
• Last Modified: 26 Sep 2025 08:30
• Thesis DOI: 10.5525/gla.thesis.85474
• URI: https://theses.gla.ac.uk/id/eprint/85474