Surface enhanced vibrational spectroscopy: Implementations in lab-on-a-chip

Research output: ThesisPhD Thesis - Research UT, graduation UT

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Abstract

The goal of this thesis, is to develop a lab-on-a-chip device for online reaction monitoring using surface enhanced vibrational spectroscopy. Vibrational spectroscopy covers techniques of infrared (IR) spectroscopy and Raman spectroscopy. Both techniques provide vibrational information, although in fundamentally different ways.
In Chapter 2 a theoretical background is presented discussing the basic techniques covered in this thesis. This theoretical chapter is followed by a literature study in Chapter 3 regarding spectroelectrochemistry. Although spectroelectrochemistry is not a major subject in this study, the two sections discussing IR spectroscopy and Raman spectroscopy provide further insight into these techniques.
In Chapter 4.a modular, microfluidic microreactor is presented. This microreactor has an integrated internal reflection element for attenuated total reflection (ATR)-IR spectroscopy. A Paal-Knorr reaction is performed as proof-of-concept. To highlight the strength of IR spectroscopy as a tool for reaction monitoring, the peaks are identified and different reaction orders of various steps of the Paal-Knorr reaction are calculated.
Chapter 5 and Chapter 6 cover surface enhanced infrared spectroscopy (SEIRS) and surface enhanced Raman spectroscopy (SERS), respectively. In Chapter 5 we discuss several different fabrication techniques to fabricate nano-rod and nano-slit nanoantennas. Furthermore we discuss FTDT simulations that can be used in order to predict the wavelength these antennas are tuned to and which configuration gives the strongest enhancement. Finally we present some very initial measurement results. Chapter 6 discusses a high-yield fabrication method for wafer-scale patterning of high-quality arrays of dense gold nanogaps, using displacement Talbot lithography. Additionally, we proof that the Au nanogaps show a significant enhancement of signal of benzenethiol molecules chemisorbed on the structure surface, with an average enhancement factor up to 1.5 × 10^6.
In Chapter 7 we discuss the promise of mid-IR waveguides and propose a fabrication process how these waveguides could be fabricated. The dimensions used to design these waveguides are based on FDE simulations and literature.
In summary, all of the components as stated in the goal above have been addressed, although full integration into a single device has not been achieved. How this can be accomplished is discussed in Chapter 8 and no major obstacles are expected.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Biomedical and Environmental Sensorsystems
Supervisors/Advisors
  • Odijk, Mathieu , Supervisor
  • van den Berg, Albert , Supervisor
  • Weckhuysen, Bert M., Co-Supervisor, External person
Thesis sponsors
Award date19 Feb 2021
Place of PublicationEnschede
Publisher
Print ISBNs978-90-365-5099-4
DOIs
Publication statusPublished - 19 Feb 2021

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