Efek Ph Terhadap Sifat Optik Fluoresensi Carbon Dots Dari Daun Adam Hawa (Rhoeo Discolor L.) Menggunakan Metode Solvotermal

Abstract

Adam Hawa leaves contain flavonoid compounds which can be used as precursors of CDs. The aim of this research was to synthesize CDs from Adam Hawa leaves and analyze the effect of pH value on optical properties. In the first stage, CDs were synthesized using the solvothermal method using 96% ethanol solvent at a temperature of 150OC for 8 hours and characterized using UV, UV Vis, FTIR, PL and TEM lights. The optical properties of CDs such as UV Vis, FTIR, PL were analyzed at pH variations of 3, 5, 7 and 9. The results showed that the CDs were successfully synthesized, confirmed by the reddish fluorescence under a 365 nm UV lamp, and the results of TEM analysis showed an even particle size distribution. -average of 3.78 nm. UV Vis analysis has an absorbance peak at a wavelength of 286 nm, PL analysis shows peak emission at a wavelength of 718 nm, and the FTIR spectra results show that the CDs formed have an OH group (3324 cm-1), C-H (2974 cm-1), C=C (1654 cm- 1), C-H (1379 cm-1), C-O (1088 cm-1), from C-O (1043 cm-1). Analysis of the optical properties of CDs of various pHs shows that the UV Vis absorbance is different and the emission peak state is independent of the pH value. CDs at pH variations of 3, 5, 7 and 9 showed peak emission wavelengths of 718 nm, 679 nm, 680 nm, 674 nm and 673 nm, respectively. QY was produced at CDs pH 5 with a value of 38.39%. It did not experience significant changes indicating the consistency and independence of the optical properties of CDs on pH values.