One-step synthesis of robust nitrogen-doped carbon dots: acid-evoked fluorescence enhancement and their application in Fe³⁺ detection

Abstract

Robust and highly fluorescent N-doped carbon dots (CDs) are obtained from a hybrid source, alginic acid and ethanediamine. During a hydrothermal process, the raw materials are propelled to form nano-size particles; these resultant CDs possess desirable functional groups on the particle surface. We have further investigated their optical performance under various pH conditions as well as their capacity for sensing metal ions. The N-doped CDs especially exhibit remarkable acid-evoked fluorescence enhancement under acidic conditions. Finally, the as-prepared CDs are tested for their ability to detect of Fe 3+ in acidic pure water and urban river water media, the fluorescence-quenching mechanism and recovery properties of the CDs/Fe 3+ mixture are also investigated.

Green synthesis of fluorescent carbon dots from carrot juice for in vitro cellular imaging

“…The O 1s spectrum shown in Fig. 3d exhibited two peaks, at 531.4 and 532.4 eV, which were assigned to the C=O and C-OH/C-O-C bands, respectively [30]. The N-H and C=O bonds presented by XPS suggested the formation of amide bonds, consistent with the FT-IR results, which indicated functionalization for synthesized carbon quantum dots of hydroxyl, carboxylic, and amino groups during the hydrothermal treatment.…”

“…2b. A broad diffraction peak centered at around 22.0° appeared due to the small size of the as-obtained CDs, and it corresponded to the (002) lattice spacing of carbon materials [30]. FT-IR spectra of as-prepared CDs are presented in Fig.…”

“…2c. Noticeably stronger peaks emerged at 3406 cm −1 , which may correspond to the stretching vibrations of O-H and N-H. A variety of peaks at 1702, 1614, 1408, and 1247 cm −1 were assigned to the stretching vibrations of C=O in ketone, stretching vibrations of C=C and C=N, and bending vibrations of −OH, respectively [21,29,30]. These results indicated that the asprepared CDs possessed abundant functional groups, which is beneficial for enhancing their PL property.…”

“…The reactor was then operated at 160°C for 6 h and cooled naturally before opening. The raw solution was subsequently centrifuged at 8000 rpm for 30 min to remove large http://carbonlett.org C-O-C, C-N, and C=O, respectively [21,30]. Similarly, the three peaks for N 1s (Fig.…”

One-step fabrication of high quantum yield sulfur- and nitrogen-doped carbon dots for sensitive and selective detection of Cr(vi)

“…[8][9][10][11] Due to the outstanding properties, CDs have been used as uorescent probes for the trace analysis of metal ions (such as Fe 3+ , Hg 2+ , Cu 2+ and Ag + , etc. ), [12][13][14][15][16][17] and some organic compounds (such as glucose, DNA, vitamin B12, and dopamine, etc.). [18][19][20][21] Recently, graphene quantum dot membrane, 22 boron and nitrogen co-doped carbon dots, 23 cobalt(II)-doped carbon dots, 24 and phosphate functionalized carbon dots 25 have all been successfully employed as probes for the determination of Cr(VI).…”