Analysis of The Optical Properties of Carbon Dots Material in Various Solvents and Changes in The Effect of External Microwave

The development of nanocarbon research on mechanical, electrical and optical properties has become one of the nanotechnology studies that has been widely developed among researchers. Carbon dots (CDs) attract many researchers because of their tunable photoluminescence (PL) properties, high quantum value (QY), low toxicity, small size, biocompatibility, and cheap and easy to obtain sources. It can be applied in various fields such as biomedicine, catalysis, optoelectronic devices, and anticounterfeiting. CDs generally have zero dimensions measuring 2–10 nm (Liu et al., 2020).
Carbon nanoparticles were first researched in 2004 through a CNT (carbon nanotube) refining process, then in 2006 it was reported that carbon particles synthesized through a laser ablation process (top down method) could produce high PL properties so that the name was changed to CDs by Sun, et al. Synthesis of CDs can be carried out with various types of precursors including; It has been reported by Liu, et al that CDs can be synthesized via citric acid and ethylendiamine precursors using the hydrothermal method (Liu et al., 2020). Slave, et al. also reported the synthesis of CDs using urea and citric acid precursors using the method of (Budak et al., 2020). Furthermore, Wibrianto, et al. reported that CDs can be synthesized with precursors of citric acid, boric acid, nitric acid, sulfuric acid, and phosphoric acid using a microwave method with hydrothermal assistance (Wibrianto et al., 2020).

The use of various solvents after the synthesis of CDs provides various effects. The physical and chemical properties can be adjusted by varying the solvent. The use of different solvents means providing many adjustments. Such as pH and solvent polarity index. This is useful for reviewing changes in optical properties that occur (He et al., 2023).