In this article carbon quantum dots (Cdots) were prepared by a facile, green, economical hydrothermal method of the mixed deionized water and lemon juice. Optical and structural properties of the Cdots have been extensively studied by UV–visible and fluorescence spectroscopy, x-ray diffraction (XRD) techniques, and high-resolution TEM (HR-TEM). | VNU Journal of Science: Mathematics – Physics, Vol. 35, No. 1 (2019) 62-69 Original article Green Emission Carbon Quantum Dots from Lemon Juice for Selective Detection of Fe 3+ Ions Bui Thi Hoan1, 2, Phuong Dinh Tam3, Vuong-Hung Pham1, * 1 Advanced Institute for Science and Technology (AIST), Hanoi University of Science and Technology (HUST), No 01, Dai Co Viet Road, Hanoi, Vietnam 2 Faculty of Energy Engineering, Thuyloi University, No 175 Tay Son, Hanoi, Vietnam 3 Faculty of Material Science and Engineering, Phenikaa University, Yen Nghia, Hanoi, Viet Nam Received 24 January 2019 Revised 20 March 2019; Accepted 21 March 2019 Abstract: In this article carbon quantum dots (Cdots) were prepared by a facile, green, economical hydrothermal method of the mixed deionized water and lemon juice. Optical and structural properties of the Cdots have been extensively studied by UV–visible and fluorescence spectroscopy, x-ray diffraction (XRD) techniques, and high-resolution TEM (HR-TEM). Surface functionality of Cdots has been illustrated by Fourier transform infrared spectroscopy (FTIR). The fabricated Cdots emit bright green light with a broad spectrum. The Cdots exhibit captivating sensitivity and selectivity toward Fe 3+ with a linear range from 0 to 80 ppm and a detection limit of ppm. Keywords: Carbon quantum dots, lemon juice, sensing Fe3+. 1. Introduction Carbon quantum dots (Cdots) have attracted special attention of scientists because of their unique optical and chemical properties. Unlike traditional dye and semiconductor quantum dots (QDs), traditional Cdots have stable optical properties, good biodegradability and low toxicity. This material attracts attention in areas such as the biological label, photocatalysis, sensing and biomedical area [1]. Cdots are carbon nanomaterial of size less than 10 nm and considered as composed of crystalline or amorphous cores with predominant carbon sp2 and abundant functional groups in the shell. During .
