A facile hydrothermal approach towards photoluminescent carbon dots from amino acids

Dual functional N- and S-co-doped carbon dots as the sensor for temperature and Fe3+ ions

“…It is well acknowledged that Fe 3+ could absorb [52] and react with the large numbers of -OH, -COOH and -NH2 groups distributing on the surface of C-dots, which led to the chelation or coordination and caused the formation of nonradiative electron/hole recombination, resulting in the consequently quenching of fluorescence [9]. Probably due to the chelating process of Fe 3+ ions with C-dots in comparison with other metal ions, the marvelous selectivity of these C-dots was able to be manifested [23]. Compared with the C-dots using only methionine as precursor, the C-dots synthesized by methionine-acrylic acid hybrid precursors possessed higher sensitivity with better limit of detection to Fe 3+ , which could be ascribed to acrylic acid-induced modulation of the chemical and electronic characteristics and its more oxygen-containing coordination groups.…”

“…Up to now, masses of efforts has been made to prepare nitrogen-doped, sulfur-doped or nitrogen-and sulfur-co-doped C-dots from natural biomass, peptide, amino acid and other small molecule, such as garlic [22], goose [23], grapefruit peel [24], hair fiber [25], cocoon silk [26] thioglycolic acid [27] and the mixture of glucose and glycine [28].Compared to bare C-dots, nitrogen-doped C-dots might not only improve fluorescence properties but also allow to apply available functional groups for target sensing. The report about nitrogen and sulfur co-doped C-dots obtained by hydrothermal treatment of citric acid and L-cysteine indicated its excellent fluorescent property was ascribed to the doping changing surface state facilitating a high yield of radiative recombination [29].…”

Carbon “Quantum” Dots for Fluorescence Labeling of Cells

“…Among more significant recent successes have been the finding and subsequent development of carbon "quantum" dots or more appropriately called carbon dots (for the lack of the classical quantum confinement effect in these nanomaterials), [4][5][6][7][8][9][10][11] which have played a leading role in an emerging and rapidly -3 -expanding research field centered on the design, preparation, and potential biomedical uses of various carbon-based QDs. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] Carbon dots are generally small carbon nanoparticles with various surface passivation schemes by organic or bio-molecules (Figure 1), 4,6,7,12 where the more effective surface passivation has been correlated with brighter fluorescence emissions from the corresponding dots. The optical absorption of carbon dots is assigned to π-plasmon transitions in the carbon nanoparticle core of the dots, while the fluorescence emissions in the visible to near-IR are attributed to photogenerated electrons and holes trapped at diverse surface sites and their associated radiative recombinations.…”

Poly(vinyl alcohol)–Carbon Nanodots Fluorescent Hydrogel with Superior Mechanical Properties and Sensitive to Detection of Iron(III) Ions

“…Carbon nanodots (CNDs), an emerging fluorescent nanomaterial, have been widely used in biomarkers, medicine, energy conversion, drug release, and ion detection owing to their excellent water solubility, low cytotoxicity, and robust optical properties compared with some conventional fluorescent substances (metal nanoparticles, semiconductor quantum dots, etc.) . Various materials associated with CNDs form their composites materials, which enhance the properties of both materials and expand the applicability of CNDs in different fields .…”