In recent years, fluorescent nanomaterials have drawn special attention over conventional fluorophores, offering great potentials for optical bioimaging, medical diagnosis, photocatalysis, and photovoltaic devices. Semiconductor quantum dots (QDs) especially those based on cadmium salts and related core-shell nanostructures have proven to have excellent performance, predictable fluorescence color variations, and long term resistance to photobleaching. However, a serious disadvantage with these popular QDs is that they contain heavy metals, such as cadmium, whose significant toxicity and environmental hazard are well documented. In the search for alternative QD-like nanomaterials, carbon-based nanomaterials have emerged as the most promising due to their relatively high quantum yields, low cost, non-toxic nature, and excellent biocompatibility. Since the original report in 2006, carbon dots have been investigated by many research groups worldwide, with great advances made in their syntheses, mechanistic understandings, and evaluations for potential bio-applications. However, despite these advances many fundamental and technological issues with C-dots still await further investigation. For example, efficient and simple strategies for the fabrication of C-dots on a large scale and with better control of their dimensions, surface chemistry, and tunable emission profiles are still challenge in this field. Herein, we report a simple one step hydrothermal method for the synthesis of highly fluorescent self-passivated carbon dots by combining various carbon sources of carboxylic acids and amine molecules. The structural and optical properties were characterized using various techniques like UV-vis and fluorescence spectroscopy, Fourier Transform Infra-Red, elemental analysis, and SEM. This method is a convenient, environment friendly, inexpensive and efficient process for large-scale production. The as-prepared carbon dots exhibited excellent water solubility, good photostability, and a high quantum yield. The implication of the results to the mechanistic framework for photoluminescence emissions will be discussed.

Hydrothermal synthesis of highly fluorescent self-passivated carbon dots

247th National Meeting (2014)

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