Synthesis of Carbon Dots with Tunable Luminescence

Abstract

Synthesis of carbon dots carried out by the method of hydrothermal treatment of carbon precursors, such as glucose, citric acid and soot from birch bark in aqueous ammonia. The lateral dimensions distribution of the carbon dots was measured, from which the average dimensions were determined, which are in the range 10-12 nm in the case of glucose, citric acid and 20-22 nm in the case of soot. Water suspensions with carbon dots from both glucose and citric acid show strong absorption in the visible region from 300 to 500 nm, while carbon dots synthesized from soot have strong absorption in the ultraviolet region but are transparent in the visible region. The infrared absorption spectra were measured, which showed the presence of oxygen groups on the surface of synthesized carbon dots. Investigation of luminescence spectra have shown that carbon dots synthesized from glucose and soot luminesce equally in the violet region of the spectrum and the wavelength of the radiation is being dependent on the excitation wavelength. The luminescence intensity depends on the carbon dots dimensions and on the presence of oxygen groups on their surface. Luminescent carbon dots synthesized from glucose, citric acid and soot are ecological, biocompatible and have great prospects for their application in the field of biology and medicine.