Insight into the Modulation of Carbon-Dot Optical Sensing Attributes through a Reduction Pathway

Abstract

Oxidized/reduced carbon dots (CDs) with tunable optical features have emerged as a new class of CDs having a common "molecular origin" but different fluorescence (FL) behaviors. In the present work, using "banana peel" as a sole carbon source followed by doping with fluorine (F), boron (B), and nitrogen (N) over CDs, banana peel-derived carbon dots (BP-CDs) were synthesized using a well-known hydrothermal synthesis method. Moreover, as-synthesized BP-CDs were further reduced to "rBP-CDs" by NaBH 4 . At post reduction, the FL performance (i.e., quantum yield) of rBP-CDs were found to be enhanced compared with the BP-CDs, along with variations in excitation and emission wavelengths. Interestingly, the optical sensing attributes of BP-CDs and rBP-CDs were varied, that is, BP-CDs selectively sense "Co 2+ with a limit of detection (LOD) value of 180 nM", whereas rBP-CDs detected Co 2+ (with an LOD value of 242 nM) as well as Hg 2+ (with an LOD value of 190 nM). To the best of our knowledge, this work presents the very first report on the modulation of CDs' sensing behavior after reduction. The modulation in the sensing behavior with the common carbon precursor and reduction paves a new possibility for exploring CDs for different commercial applications.

Portable and non-invasive fluorescent thin films from photocatalytically active carbon dots for selective and trace-level detection of picric acid

“…Fig. 3d shows the intensity variation vs. PA concentrations plot, revealing a linear relationship (with an excellent correlation coefficient, R 2 , of 0.9976), and a LOD of 104 nM determined using eqn (2). The value of the quenching constant was found to be 2.8 Â 10 À2 M À1 calculated using eqn (3).…”

“…In the past decade, carbon dots (CDs) have been proven to be an efficient fluorescent (FL) sensor due to their exceptional and stable luminescence properties with minimal photobleaching and excellent biocompatibility. [1][2][3] The abundance of various precursor molecules and simple synthetic routes with ease of surface modification make CDs quite versatile and highly useful in myriad applications such as sensing, 4 bio-imaging, 5 drug delivery, 6 energy storage, 7 photodynamic therapy, 8 photocatalysis, 9 etc. Recent studies have shown that the CD structure could be more effectively controlled by the wise selection of the carbon precursor.…”

Application and Research Status of Long-Wavelength Fluorescent Carbon Dots

“…Compared with traditional fluorescent materials, CDs exhibit low toxicity and high biocompatibility, thereby reducing the risk of side effects when they enter the body [47,48]. Additionally, most CDs are water-soluble, which simplifies sample preparation by avoiding the need for complex pre-treatment procedures.…”