Luminescent nanomaterials are encouraging scaffolds for diverse applications such as chemical sensors and biosensors, imaging, drug delivery, diagnostics, catalysis, energy, photonics, medicine, and so on. Carbon dots (CDs) are a new class of luminescent carbonaceous nanomaterial that have appeared recently and reaped tremendous scientific interest. Herein, we have exploited a simple approach to prepare tuneable and highly fluorescent CDs via surface functionalization. The successful synthesis of CDs is manifested from several investigations like high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The CDs exhibit excellent water solubility and with increasing nitrogen content fluorescence quantum yield increases whereas cell toxicity decreases. The CD synthesized at high temperature (180 °C) shows very high quantum yield (more than 56%). The tuneable optical properties of CDs are systematically studied using UV-vis and fluorescence spectroscopy. The cell viability evaluation and in vitro imaging study reveals that the synthesized CDs can be employed as a potential fluorescent probe for bio-imaging without further modification.
Bibliographical noteFunding Information:
This work was partially supported by the Priority Research Centers Program ( 2009-0093823 ), and the Korean Government (MSIP) (No. 2015R1A5A1037668 ), Brain Korea 21 plus (BK21) project grant funded by Korea government, Korea Ministry of Environment as “Global Top Project” ( 2016002130005 ), and Development of diagnostic system for mild cognitive impairment due to Alzheimer's disease ( 2015-11-1684 ), Nano·Material Technology Development Program ( NRF-2017M3A7B4041987 ).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Colloid and Surface Chemistry