One-pot Solvothermal Synthesis of Full-color Carbon Quantum Dots for Application in Light Emitting Diodes

Optical and Sensing Properties of Carbon Colloidal Particles Based on (Thio)urea and Citric Acid: Effect of the Components Ratio

“…We considered a wide range of compositions of urea-citric acid mixtures subject to solvothermal treatment in this study. Since the properties of the so-obtained nanoparticles were expected to strongly depend on the nature of the solvent used in the synthesis [4], we compared our results with the available reports on relevant solvothermal preparations in dimethylformamide [4,14,[26][27][28]. In general, our findings coincided with the properties of carbon nanodots prepared in other studies in excess of urea or at a 1:1 mass ratio of the precursors [4,14,26,28] as well as in slight excess of citric acid [4,27]: the multicolor excitation-dependent fluorescence of the solvothermal treatment products was observed.…”

“…Since the properties of the so-obtained nanoparticles were expected to strongly depend on the nature of the solvent used in the synthesis [4], we compared our results with the available reports on relevant solvothermal preparations in dimethylformamide [4,14,[26][27][28]. In general, our findings coincided with the properties of carbon nanodots prepared in other studies in excess of urea or at a 1:1 mass ratio of the precursors [4,14,26,28] as well as in slight excess of citric acid [4,27]: the multicolor excitation-dependent fluorescence of the solvothermal treatment products was observed. Important progress made in our study was the direct examination of the synthesized nanoparticles by means of the NTA technique, without isolation for TEM study.…”

High Quantum Yield Nitrogen-Carbon Dots (N-CDs) from Plastic Waste

“…1 displayed the UV-Visible spectra of N-CDs and a maximum absorption band was observed at around 289 to 300 nm assigned to electron transition of π-π* from the carbonic core, which suggested the conjugated system of C=C in the N-CDs structure 6,14) . The broad absorption up to 500 nm referred to the presence of electron excitation from n-π* attributed to the heteroatomic surface functionalities of N-CDs 9,22) . Furthermore, based on UV-Visible spectra, the rise of H2O2 concentration as an oxidant from 0 (N-CDs 06) to 3 (N-CDs 36) and up to 5 wt.% (N-CDs 56) can increase the absorbance of CDs obtained and cause the absorption band to broaden towards longer wavelengths.…”

“…Researchers are captivated by the remarkable characteristics of CDs, including their fluorescence capability, excellent stability, minimal toxicity, strong compatibility with living organisms, and their ability to act as both electron donors and acceptors 5) . These unique properties make CDs highly promising for a diverse array of applications, such as bio-imaging 6) , drug delivery 7) , contaminant detection 8) , LED 9) , solar cells 10) , photocatalysis 11) , and corrosion inhibitors 12) . The synthesis of CDs by subjecting waste plastic bags to hydrothermal conditions at 180 °C for 12 h has been investigated by Hu et al 4) .…”

Natural Nitrogen-Doped Carbon Dots Obtained from Hydrothermal Carbonization of Chebulic Myrobalan and Their Sensing Ability toward Heavy Metal Ions

“…Due to the outstanding physicochemical, optical, and biological characteristics, carbon dots have had widespread attention from several important sectors such as sensor/biosensor, catalysis, biomedical, wastewater purification, optoelectronic device, and anti-counterfeiting issues [ 10 , 11 , 12 , 13 ]. Several methods have been proposed for synthesizing carbon dots such as microwave heating, laser ablation, arc-discharge, electrochemical oxidation, plasma treatments, combustion/thermal pyrolysis, solvothermal heating, and hydrothermal carbonization methods [ 14 , 15 , 16 , 17 , 18 ]. Compared with other methods, the hydrothermal carbonization route with natural precursors shows significant advantages such as a simple setup, being green/clean and environmentally friendly, and a cost-effective design [ 19 , 20 , 21 ].…”