Sintesis dan Karakterisasi Carbon Dots (CDs) Berbasis Cangkang Biji Karet (Havea brasiliensis) Menggunakan Metode Hidrotermal

Abstract

Rubber seed shells (Hevea brasiliensis) are agricultural biomass waste that is abundant and has not been optimally utilized. Rubber seed shell biomass can be used as a precursor in the synthesis of Carbon Dots (CDs). CDs are carbon nanomaterials with particle sizes less than 10 nm that have high fluorescence properties and good stability, making them potentially useful in various applications. This study aims to synthesize and characterize rubber seed shell-based CDs. Rubber seed shell biomass was carbonized at 350°C for 6 hours, then pulverized to obtain rubber seed shell powder. CDs were synthesized using the hydrothermal method at temperatures of 160, 180, and 200°C for 16 hours, then centrifuged at 5000 rpm for 15 minutes. The results showed that CDs were successfully synthesized, as confirmed by the formation of blue fluorescence under a 365 nm UV lamp and TEM analysis showing a spherical morphology with an average particle size distribution of 4.6 nm. The FTIR spectrum showed the presence of O–H, C–H, C=C, and C-O groups on the surface of CDs. Photoluminescence analysis showed emission peaks at wavelengths of 445, 454, and 435 nm, respectively, for temperature variations of 160, 180, and 200°C. The UV-Vis spectrum shows absorption peaks at 245 nm, 268 nm, and 224 nm for each heating temperature of 160, 180, and 200°C with respective bandgap energies of 3.12, 3.07, and 3.33 eV. The quantum yield values for each hydrothermal CDs temperature variation were 32.4627%, 35.0765%, and 27.0171%. The results of this study indicate that rubber seed shells have the potential to be used as precursors in CDs synthesis, with optimal conditions obtained at a temperature of 180 °C, which produces the maximum QY value and minimum band gap energy.