University of Kashan Journal of Nanostructures 2251-7871 11 2 2021 04 01 Novel Carbon Quantum Dots: Green and Facile Synthesis, Characterization and its Application in On-off-on Fluorescent Probes for Ascorbic Acid 236 242 111480 10.22052/JNS.2021.02.004 EN Amjad Hussein Altajer Department of pharmaceuticals, college of pharmacy, Almaaqal University, Iraq Syahril Efendi Fasilkom-TI, Universitas Sumatera Utara, Medan, Indonesia Abdullah Hasan Jabbar Optical Department, College of Health and Medical Technology, Sawa University, Ministry of Higher Education and Scientific Research, Al-Muthanaa, Samawah, Iraq Salim Oudah Mezan General Directorate of Education in Al-Muthanna Governorate, Ministry of Education, Republic of Iraq Lakshmi Thangavelu Department of Pharmacology, Dental College and Hospital, Institute of medical and Technical Sciences, Saveetha university, Chennai, India Mustafa M. Kadhim Department of Dentistry, Kut University College, Kut, Wasit 52001, Iraq Ayad M F. Alkai College of science for women, University of Babylon, Iraq Journal Article 2021 06 16 Nanostructures have proved to be a very attractive option for sensor application due to their physical and chemical properties. In recent years, carbon quantum dots as a new member of carbon nanostructures has been widely used in the field of sensors. In this work, carbon quantum dots was synthesized via green precursors using hydrothermal method. The prepared products were characterized via with X-ray diffraction (XRD) analysis, Transmission Electron Microscopy (TEM), FT-IR, UV-Vis, and Photoluminescence (PL) spectroscopy. The results revealed that the prepared carbon quantum dots provide excitation-dependent fluorescence emission. The obtained findings from photoluminescence spectroscopy revealed that as-prepared carbon quantum dots could be applied as a fluorescent probe for detection of ascorbic acid. The PL of carbon quantum dots can be significantly quenched by Cr(VI), which follows a dynamic quenching mechanism. As ascorbic acid enters the solution, Cr(VI) reduced to Cr(III) which cause the turn back the carbon quantm dots fluorescence and a good linearity in range of 0.06–0.18 mM. https://jns.kashanu.ac.ir/article_111480_6bbc18cc9130c5695789a20598b6ec73.pdf