Green preparation of versatile nitrogen-doped carbon quantum dots from watermelon juice for cell imaging, detection of Fe3+ ions and cysteine, and optical thermometry

Green Preparation of Fluorescent Nitrogen-Doped Carbon Quantum Dots for Sensitive Detection of Oxytetracycline in Environmental Samples

“…Actually, fluorescence analysis has the advantages of high sensitivity, low cost, and simple operation, which has aroused great interest in the detection field [ 20 , 21 , 22 ]. Moreover, the fluorescence method can be applied to the detection of various organic pollutants and metal ions in the environment, including antibiotics (OTC [ 3 ], tetracycline [ 23 , 24 ], chlortetracycline [ 24 ], enrofloxacin [ 25 ]), metal ions (Au 3+ [ 26 ], Hg 2+ [ 27 , 28 ], Fe 3+ [ 24 , 29 , 30 ]), pesticides [ 31 , 32 ] 2,4,6 trinitrophenol [ 33 , 34 ], glutathione [ 35 , 36 ], and chitosan [ 37 ].…”

Carbon quantum dots derived from the extracellular polymeric substance of anaerobic ammonium oxidation granular sludge for detection of trace Mn(vii) and Cr(vi)

“…The peak at 1388 cm À1 was due to the bending vibration of the -OH bond, while the peak at 1270 cm À1 was indicative of the C-N bond. 8,17 The band at 1020 cm À1 was assigned to the asymmetric and symmetric vibration of C-O-C bond, indicating the presence of -COOH groups. The peak at 770 cm À1 was owing to the out-ofplane bending vibration of N-H bond.…”

“…S3 †), which is higher than that of many reported studies. 8,10,24,33 The high quantum yield may be benecial to enhance the sensitivity of the detection of metal ions.…”

“…Recently, the uorescent probe techniques that utilize the carbon quantum dots (CQDs) or quantum dots (QDs) show a great potential as simple, fast, sensitive and selective means to determine the concentration of the heavy metals. 8 CQDs, dened as the carbon particles with size less than 10 nm, have been applied as uorescence-based sensor of a variety of metal ions. Li et al (2015) developed nitrogen and sulfur co-doped carbon dots to sensitively and selectively determine the concentration of Hg(II) ions.…”

Implementing Defects for Ratiometric Luminescence Thermometry

“…Their emission is dependent on temperature, because it is affected by the electronic transitions between vibrational states responsible for luminescence. The luminescent properties of QDs, which result from the recombination of the electron–hole pair are strongly dependent both on the host material composition as well as their size [ 5 , 6 , 7 ]. In this case, the phonon-related depopulation processes and the energy gap are strongly temperature dependent.…”