Particulate, Structural, and Optical Properties of D-Glucose-Derived Carbon Dots Synthesized by Microwave-Assisted Hydrothermal Treatment

Abstract

Environmentally friendly and visible fluorescent carbon dots (CDs) have received attention as alternatives to compound semiconductor quantum dots containing toxic elements. Hydrothermal reaction of water-soluble carbohydrates can provide an eco-friendly and facile synthesis approach to CDs. In this study, we have attempted to efficiently produce uniform CDs using a microwave heating system that can maintain the reaction solution at a constant temperature. We synthesized CDs from D-glucose through hydrothermal treatment at 200 • C for 5-60 min. From transmission electron microscopy, the particle size of the CDs increased in proportion to the hydrothermal duration. Furthermore, the absorbance and maximum photoluminescence intensity of the CDs aqueous dispersions (10 mg L −1 ) increased with an increase in hydrothermal duration. The maximum photoluminescence intensity of the dispersions decreased at pH < 4 and pH > 10; the absorbance at the excitation wavelength remained unchanged. These results indicate that the number of emission sites and absorption sites increased with an increase in the particle size and that emission sites were located near the surface of the obtained CDs.

Glycothermally Synthesized Carbon Dots with Narrow-Bandwidth and Color-Tunable Solvatochromic Fluorescence for Wide-Color-Gamut Displays

“…In fact, CDs prepared from d -glucose and l -cysteine in our previous reports did not show the solvatochromic behavior. 31 , 50 , 51 Fluorescence solvatochromism for CDs has recently received a great deal of attention as their color tuning strategy and studied because CDs prepared from an aromatic compound of p -phenylenediamine showed the solvatochromic behavior. 33 , 34 , 52 CDs prepared from aromatic compounds possessed π-conjugated systems, and their emission peaks shifted to longer wavelengths as the solvent polarity increased, that is, positive fluorescence solvatochromism.…”

Precursor Concentration Effect on Optical Properties of Carbon Dots from Cassava’s Peels

“…In this case, increasing the precursor concentration will increase the amount of C-dots formed. PL of C-dots are not caused by transition bandgap but surface transition state on bandgap (Yoshinaga, Iso, & Isobe, 2018). PL peaks undergo successive red shifts with increasing precursor concentrations from 0.25%, 0.5%, 1.0% and 2.0% are 509.82 nm, 515.79 nm, 519.00 nm and 524.51 nm, respectively.…”

Spectroscopy Study of Polyvinyl Alcohol/Carbon Dots Composite Films

“…The measurement of the average lifetime of C-dots can be obtained using Eq. (2) [30][31][32][33][34]. The time-resolved photoluminescence spectra of C-dots can be seen in Figure 4.…”