Gel-like Carbon Dots: Characterization and their Potential Applications
Carbon dots, Gels, Invisible inks, Photoluminescence, Quantum dots
Highly photoluminescent gel-like carbon dots (G-CDs) were successfully synthesized for the first time by a rapid one-step solvothermal synthesis approach with citric acid and 1,2-ethylenediamine as the precursors. Their gel-like nature was revealed by the Tyndall and coagulation effects, which were elucidated by a negative ζ potential value. The influences of temperature on the properties and sizes of these G-CDs were analyzed, and the best method for a maximum quantum yield was identified. The resulting products emitted blue photoluminescence under UV light (λ=365 nm) and a gradient of color under regular light. In addition, the UV/Vis absorption and fluorescence emission spectra of the G-CDs indicated that those synthesized at 160 °C exhibited the highest fluorescence quantum yield (33 %). Atomic force microscopy and transmission electron microscopy measurements were performed, and a higher temperature of formation resulted in smaller G-CDs. Furthermore, band shifts in the UV/Vis and fluorescence spectra and sequential changes in the quantum yield values and ζ potentials in addition to elemental compositional changes as determined by X-ray photoelectron spectroscopy were monitored throughout the formation process of the G-CDs. As to applications, G-CDs were prepared as an invisible ink for printers, which exhibited the applicability of G-CDs in daily life and military activities.
Yiqun Zhou, Alexandra Desserre, Shiv Sharma, Shanghao Li, M. Hensley Marksberry, Charles C. Chusuei, Patricia Blackwelder, and Roger M. Leblanc. 2017. Gel-like Carbon Dots: Characterization and their Potential Applications .ChemPhysChem , (8) : 890 -897. https://nsuworks.nova.edu/occ_facarticles/847.