Hobbie, ErikAlharthi, Naif Saad2024-12-262024https://hdl.handle.net/20.500.14154/74448The content presented in this PhD dissertation has been published in highly reputable journals, including ACS Nano, one of the top 5% journals in the field of nanoscience, as well as other prestigious journals within the discipline.By using non-thermal plasma (NTP) synthesis, we generated 2D silicon carbide (SiC) nanocrystals (NCs) from a liquid precursor tetramethylsilane (Si(CH3)4) (TMS). These NCs have a distinct surface emission. By working in an oxygen-shielded environment, we obtain high photoluminescence quantum yields (QYs) of nearly 70% which present a high efficiency of emission. Microscopy analysis (TEM/AFM) shows that the NCs have a size of about 5-10 nm and a very small thickness of under one nanometer (1 nm). X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) confirm their crystallinity and thickness. Raman spectra also confirm crystallinity relative to the bulk, indicative of crystalline quasi-2D material and the layered structure of the flakes.FTIR analysis reveals Si-OCxHy groups on the surface of the SiC NCs. These functional groups play a significant role in the light emission of these confined 2D particles. These discoveries collectively provide additional insights about the complex relationship between the surface of the nanocrystal and the quantum confinement that affects how light energy is used in these materials. In a connected manner, SiC QDs-based polymer nanocomposites (PNCs) have been synthesized and investigated for their radiative emission dynamics. These materials have attracted significant interest due to their wide range of potential applications, including new biolabeling and solar-collection technologies. While the nature of photoluminescence (PL) relaxation in 2D layered vitrified colloidal silicon-carbide (SiC) nanocrystals (NCs) is still under investigation, efficient PL from SiC QDs polymer nanocomposites has been achieved. In this study, we investigate the radiative emission dynamics and cryogenic photoluminescence response of a novel two-dimensional silicon carbide nanocrystal-polymer composite synthesized via the off-stoichiometric thiol-ene process. To delve into the details, we used four-functional thiol, three-functional allyl, and a group of dodecyl-covered two-dimensional stacked silicon carbide (SiC) nano crystals (NCs) to make a series of polymer/nanocrystal composites. We looked at how the emission wavelength, quantum yield, and temperature changed, especially the changes in PL dynamics when cooled to cryogenic conditions.115en-USQuantum Dots (QDs)Semiconductors2D-NanomaterialsPolymer NanocompositesNon-Thermal PlasmaQuantum Yiled (QY)Photoluminescence (PL)Thesis