Green Synthesis of Carbon Quantum Dots using Hydrothermal Method

Abstract

Nanotechnology, especially nanomaterials, plays vital roles in many technological advances in the world and many special techniques were use to develop those materials for multifunctional uses. While nanomaterials have many potential benefits, they can create toxic effect of nanoparticles on living cells. It brings many researchers to invent low toxic and cells compatible nanomaterial. This work proposed a green synthesis of carbon dots with hydrothermal method using agriculture waste from mangosteen pericarp as a carbon source. After synthesized with hydrothermal temperature in condition 170◦C - 240◦C, the strongest emission intensity occurred at 200◦C temperature condition and a strong peak was found at wavelength 438 nm within range of blue color and the averaged size was about 3.1± 0.06 nm. At the lowest emission intensity 170◦C, strong emission peak was at wavelength 502 nm with average size of 7.2± 0.04 nm. The results were consistent with theory of quantum size effect, that the band gap energy of quantum dot is inversely size dependent. In addition, if hydrothermal temperature was over 200◦C, carbon core of the dots would be agglomerated and their fluorescence intensity decreased, while hydrothermal temperature were increasing.