On the Luminescence Properties of Carbon Dots Synthesized on the Basis of Nile Red Laser Dye

• Published in: Surface investigation, x-ray, synchrotron and neutron techniques Vol. 18; no. 1; pp. 100 - 105
• Main Authors: Nelson, D. K., Starukhin, A. N., Kurdyukov, D. A., Eurov, D. A.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.02.2024; Springer Nature B.V
• Subjects: Absorption spectra; Carbon; Carbon dots; Chemistry and Materials Science; Colloids; Deionization; Dyes; Electron states; Fluorescence; Hydrofluoric acid; Luminescence; Materials Science; Optical properties; Pyrolysis; Surfaces and Interfaces; Synthesis; Temperature dependence; Thin Films; carbon dots; temperature dependence; fluorescence; Nile Red dye
• ISSN: 1027-4510; 1819-7094
• DOI: 10.1134/S1027451024010142

The temperature dependence of the fluorescence of a colloidal solution of carbon dots in glycerol is studied. The dots are obtained by the pyrolysis of Nile Red laser dye using mesoporous silica as a matrix. To obtain a colloidal solution of individual dots, the matrix material is dissolved in hydrofluoric acid, followed by repeated cleaning of the dots with deionized water. The optical absorption spectrum of the dots demonstrates the presence in their composition of aromatic sp 2 -hybridized carbon atoms, as well as CO and CN molecular groups. The fluorescence spectrum of the colloidal solution when excited by light with λ exc = 405 nm consists of two emission bands. It is established that the intensity I of the main (long-wavelength) fluorescence band of the synthesized dots increases with increasing solution temperature T in a wide temperature range from 270 to 415 K. The nature of the dependence I ( T ) indicates the occurrence of two competing processes: thermally induced fluorescence quenching and its enhancement. A three-level model of electronic states is considered, within which the observed temperature dependence of fluorescence is quantitatively described and the energies of nonradiative deactivation and activation of the emissive state are estimated. The nature of the electronic state responsible for the nonradiative activation of the emissive state is discussed.