Synthesis and modulation of the optical properties of carbon quantum dots using microwave radiation

Facile Synthesis of Surface-Modified Carbon Quantum Dots (CQDs) for Biosensing and Bioimaging

“…What is interesting, the choice of the modifying agent affected the PL properties in various ways and there was no general tendency for all of the samples, similarly as in the case of the optical characteristics of the products. The fluorescence of the prepared samples was a result of the disruption of the crystalline structure along with the band gap transitions (conjugated π-type bonds), which is characteristic for carbon quantum dots [ 5 , 6 , 14 , 20 , 25 , 29 , 30 ]. Figure 7 presents the CQDs solutions irradiated with the commercially available diode, which exhibit blue fluorescence at λ = 365 nm.…”

“…All of the samples exhibited two maxima when excited at 320 nm, 340 nm and 360 nm, except for CQDs-1 sample, which had two maxima when excited at 320 nm and 340 nm. The obtained results were typical for carbon quantum dots and could be attributed both to the various functional groups present on the surface of the CQDs as well as due to the quantum effect, which is assigned to the different sizes of the particles [5,6,9]. The spectra given in the Figure 6 shows that the highest fluorescence intensity was obtained for the CQDs-2 sample, which was prepared from aminoglucose and modified with urotropin and CQDs-8 prepared from cellulose and modified with the same compound.…”

“…The investigated CQDs exhibited excellent QY stability over time (up to 0.3% after one week), which is a great advantage comparing to the traditional organic dyes that easily undergo photobleaching. Thus, they have great potential in biomedical applications [6,9,14,29,30,32]. Carbon quantum dots prepared by top down methods without post modification in most cases do not contain functional groups that are responsible for pH-sensitivity.…”

“…Nanomaterials are widely applied for detecting assays production with active optical elements. The most promising ones involve the application of quantum dots (QDs) due to their unique properties such as superior resistance to photobleaching [ 4 , 5 , 6 , 7 ]. Tools for biodetection based on QDs enable reversible quantification and detection of various biomolecules attracts a lot of scientists’ attention since they have a lot of advantages comparing to traditionally used classic organic fluorophores.…”

A review on advancements in carbon quantum dots and their application in photovoltaics

“…In comparison to hydrothermal synthesis, the microwave irradiation method is faster, requires a lower temperature and can be halted at any time to avoid overheating the sample. 36 In recent years, this synthetic technique has received signicant attention due to its rapid, cost-effective, easily scalable, energy-efficient, 37 and ecofriendly nature, 7,23 but it is difficult to precisely control the size of CQDs with this method. 7 In this method, the aqueous solution consisting of carbon precursors is heated in the microwave oven till the CQDs are synthesized.…”