lOU, Jun2023-06-132023-052023-04-19May 2023Nguyen, Christine Chau. "Synthesis, processing, and electrochemical performance of two-dimensional materials for sensing applications." (2023) Diss., Rice University. <a href="https://hdl.handle.net/1911/114905">https://hdl.handle.net/1911/114905</a>.https://hdl.handle.net/1911/114905Two-dimensional (2D) transition metal dichalcogenides (TMDs) have shown potential for the development of high-performance electronic devices and sensors due to their mechanical robustness, high-electron mobility, and high sensitivity and selectivity of analytes. To elicit these properties, optimization of material synthesis and processing must be performed prior to implementing TMDs into devices. Conventional methods of synthesizing and processing can achieve single to few-layered TMDs; however, there is no precision or control over its patterning at specific desired locations, which are necessary attributes for fabrication of electronics and sensors. Furthermore, the selectivity and sensing capabilities of 2D TMDs could be further explored. This thesis examines laser-based techniques for processing of monolayer MoSe2 that offers precise and controlled patterning of materials. By varying both the laser wavelength and powers we discovered Se vacancies can be photothermally induced in the laser treated area. We also investigate potential 2D materials-based coatings to detect analytes found in the human body which can be used as a screening process for health diagnostics and monitoring purposes. 2D TMD based sensors have shown to be biocompatible as well as sensitive to biomolecules which makes them great candidates for biosensors. Nitric oxide (NO) is a signaling molecule in the body that relates to circulation and neurotransmission. Extreme levels of NO concentration are indicative of health issues including high blood pressure, chronic kidney disease, and neurodegenerative diseases. We demonstrate the development of 2D materials-based biosensing coatings – FeS and MoS2– on acupuncture needles for NO detection. We performed in vitro and ex vivo electrochemical assessments on the developed coatings and they exhibited both sensitivity and selectivity towards NO. The scope of this thesis addresses the challenges of material fabrication and device performance: achieving high quality, uniform distribution, single crystal orientation, and morphology of TMDs through laser-processing. Through the development of high analyte sensitivity and selectivity of 2D materials we can integrate these systems for device and sensing applications.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.two-dimensional materialslaser processingelectrochemical sensingtransition metal dichalcogenidesmaterials synthesis and characterizationThesis2023-06-13