Fabrication and photoluminescent properties of Tb3+ doped carbon nanodots

Abstract

Carbon nanodots (CNDs) doped with Tb ions were synthesized using different synthetic routes: hydrothermal treatment of a solution containing carbon source (sodium dextran sulfate) and TbCl3; mixing of CNDs and TbCl3 solutions; freezing-induced loading of Tb and carbon-containing source into pores of CaCO3 microparticles followed by hydrothermal treatment. Binding of Tb ions to CNDs (Tb-CND coupling) was confirmed using size-exclusion chromatography and manifested itself through a decrease of the Tb photoluminescence lifetime signal. The shortest Tb photoluminescence lifetime was observed for samples obtained by hydrothermal synthesis of CaCO3 microparticles where Tb and carbon source were loaded into pores via the freezing-induced process. The same system displays an increase of Tb photoluminescence via energy transfer with excitation at 320–340 nm. Based on the obtained results, freezing-induced loading of cations into CNDs using porous CaCO3 microparticles as reactors is proposed to be a versatile route for the introduction of active components into CNDs. The obtained CNDs with long-lived emission may be used for time-resolved imaging and visualization in living biological samples where time-resolved and long-lived luminescence microscopy is required.

Advanced Technique for In Situ Raman Spectroscopy Monitoring of the Freezing-Induced Loading Process

“…It has been shown that in comparison with the traditional methods, such as sorption from solution and coprecipitation, the FIL technique provides more efficient and controlled sorption of active substances and nanoparticles on the surface of porous micron and submicron particles. The FIL method finds application in obtaining composite particles, drug delivery systems, , carbon nanodots (CNDs), fluorescent microcapsules, , optoacoustic contrast agents, contrast agents for MRI, photocatalytic particles, etc.…”