Highly crystalline carbon dots from fresh tomato: UV emission and quantum confinement

Abstract

In this article, fresh tomatoes are explored as a low-cost source to prepare high-performance carbon dots by using microwave-assisted pyrolysis. Given that amino groups might act as nucleophiles for cleaving covalent bridging ester or ether in the crosslinked macromolecules in the biomass bulk, ethylenediamine (EDA) and urea with amino groups were applied as nucleophiles to modulate the chemical composites of the carbon nanoparticles in order to tune their fluorescence emission and enhance their quantum yields. Very interestingly, the carbon dots synthesized in the presence of urea had a highly crystalline nature, a low-degree amorphous surface and were smaller than 5 nm. Moreover, the doped N contributed to the formation of a cyclic form of core that resulted in a strong electron-withdrawing ability within the conjugated C plane. Therefore, this type of carbon dot exhibited marked quantum confinement, with the maximum fluorescence peak located in the UV region. Carbon nanoparticles greater than 20 nm in size, prepared using pristine fresh tomato and in the presence of EDA, emitted surface state controlled fluorescence. Additionally, carbon nanoparticles synthesized using fresh tomato pulp in the presence of EDA and urea were explored for bioimaging of plant pathogenic fungi and the detection of vanillin.

Green Synthesis of Fluorescent Carbon Dots from Cherry Tomatoes for Highly Effective Detection of Trifluralin Herbicide in Soil Samples

“…So, 180 °C and 6 h was chose as the optimal reaction temperature and time, respectively. Under the optimized conditions, the quantum yield (QY) of the pristine CQDs was calculated to be around 9.7%, which was higher than the QY of pristine carbon dots (1.77%) according to the reported results of Liu et al …”

Fe3+-Sensitive Carbon Dots for Detection of Fe3+ in Aqueous Solution and Intracellular Imaging of Fe3+ Inside Fungal Cells

“…But fluorescence intensity of the carbon dots was independent on pH in the ranges of 2-4 and 7-9. Protonation-deprotonation occurring on the surface of the carbon dots with pH variation induced the changes in the surface charges, resulting in pHdependence (Hu et al, 2014;Yuan et al, 2016;Liu et al, 2017). Therefore, if the carbon dots are used as bioimaging agents under the physiological pH condition, fluorescence intensity will hardly suffer from the pH variation.…”

Biomolecule-derived quantum dots for sustainable optoelectronics

“…1,[31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] Plant extracts have been demonstrated to be exceptional sources for the green fabrication of biodots, especially C-QDs and G-QDs, since they are rich carbon-containing species. 1,[31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] Plant extract-derived QDs have shown tremendous physical features including high photoluminescence quantum yield (QY), photostability, excellent water solubility and lower cytotoxicity compared to ordinary dye and metal-based QDs, and thus demonstrated application potential in bioimaging, biosensing, photocatalysis and optoelectronics. 1,2,[31][32][33]…”

“…The added advantages of scalability, biocompatibility and costeffectiveness of biomolecule-derived QDs in addition to their tunable and superior optical features make them alternative and smart choices compared to conventional semiconductor QDs for applications ranging from biodiagnostics to optoelectronics. Accordingly, different biomolecules such as plant extracts including fruits, seeds, peels, leaves, owers, roots and vegetables, [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] sugars including monosaccharides and polysaccharides, [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69] different amino acids and proteins, [70][71][72][73][74][75][76]…”