Title : Synthesis, characterization, and applications of carbon quantum dots
Abstract:
Carbon quantum dots (CQDs), which are also referred to as carbon dots (CDs), are new nanomaterials based on fluorescent carbon that are zero-dimensional. The exceptional optical qualities of CQDs, along with their water solubility, biocompatibility, low toxicity, Eco-friendliness and straight forward synthesis routes. In this study, carbon quantum dots (CQDs) extracted from cow milk and lime were synthesized in a single step using a novel hydrothermal process. The samples were characterized using a variety of methods, including transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis), Fourier-transform infrared (FTIR), X-ray photoelectron (XPS), and photoluminescence (PL) spectroscopy. CQDs have quasi-spherical structures with an average particle diameter of 7 nm, according to TEM analysis. According to the XPS results, CQDs are primarily composed of carbon (67.36%), nitrogen (9.91%), and oxygen (22.73%). The high C and O content indicates that the particles have a lot of carboxyl groups on the surface. They have broad excitation-emission spectra, and excitation-dependent emission. This behavior could be attributed to the CQDs' varying sizes, random distribution, and the presence of various organic functional groups on their surfaces. At various temperatures, there is also an observed variation in the PL intensity of CQDs. The figures show that PL intensity decreases as temperature rises, and that this variation is constant across all wavelengths. This intensity drop could be the result of thermally activated non-radiative trapping increasing non-radiative relaxation at high temperatures. Despite being exposed to a lot of salt, UV light, and storage time, they stayed relatively stable. Since mechanisms for quenching fluorescence are selective and sensitive to Sn2+ , they can be employed to create a nanosensor for detecting Sn2+.
