Organosilane-functionalized carbon quantum dots and their applications to “on-off-on” fluorometric determination of chromate and ascorbic acid, and in white light-emitting devices
- 76 Downloads
Organosilane-functionalized carbon quantum dots (Si-CQDs) were synthesized by reacting glucosamine and 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane in acetone. The surface morphology, crystal structure, functional groups, elemental composition, and optical properties of the Si-CQDs were characterized using TEM (HRTEM), XRD, FT-IR, XPS, UV-vis absorption and fluorescence spectroscopy. They show that N-containing groups including C=N and C-N, and Si-containing groups including Si-O-C and Si-O-Si have been formed on the surface of Si-CQDs. The element doping and surface functionalization of Si-CQDs endow their novel chemical, physical and optical properties. The Si-CQDs dispersed in acetone are almost monodisperse with an average particle diameter of 3.6 nm. The Si-CQDs dispersed in acetone display blue fluorescence (excitation/emission maxima of 380/460 nm). In contrast, the solid-state Si-CQDs exhibited yellow fluorescence (with excitation/emission maxima of 470/595 nm). The fluorescence emission spectra of acetone-suspended Si-CQDs are concentration-dependent, and the emission peak becomes red-shifted as the concentration is increased. The Si-CQDs are sensitive and selective fluorescent “on off on” nanoprobes for chromate [Cr(VI)] and ascorbic acid (AA). Fluorescence is quenched by Cr(VI) via an inner filter effect from the absorption of Si-CQDs excitation at 380 nm by Cr(VI). Upon addition of AA, fluorescence is restored because of reduction of Cr(VI) by AA. Under optimal conditions (excitation/emission wavelength of 380/460 nm), the response is linear in the 0.4–160 μM Cr(VI) concentration range, and the detection limit is 34 nM. The respective data for AA are 1–80 μM and 84.6 nM. The practical use of the nanoprobe for Cr(VI) determination in real river water samples is also demonstrated successfully. Their concentration-dependent fluorescence, good thermal stability and self-crosslinking behavior also make the Si-CQDs a candidate material for white light-emitting diodes that displays color conversion and can act as an encapsulation layer in a blue light-emitting diode (LED) chip.
KeywordsSolid-state fluorescence Concentration-dependent fluorescence “On off on” nanoprobe Fluorescence detection Detection mechanism Inner filter effect Self-cross linking Good thermal stability Solvothermal
This study was supported by the National Nature Science Foundation of China (Nos. 31890773, 31570567), Fundamental Research Funds for the Central Universities (Nos. 2572018AB02).
Compliance with ethical standards
Conflict of interest
The author(s) declare that they have no competing interests.
- 3.Liu YS, Li W, Wu P, Ma CH, Wu XY, Xu MC, Luo S, Xu Z, Liu SX (2019) Hydrothermal synthesis of nitrogen and boron co-doped carbon quantum dots for application in acetone and dopamine sensors and multicolor cellular imaging. Sens Actuators B: Chem 284:34–43. https://doi.org/10.1016/j.snb.2018.10.075 CrossRefGoogle Scholar
- 4.Gui R, Hui J, Wang Y, Jie S (2017) Ions-induced two-photon fluorescence dual-switching for reversible and simultaneous sensing of Cu2+ and Hg2+ based on dual-emitting carbon dot/carbon dot conjugates. Sens Actuators B: Chem 245:386–394. https://doi.org/10.1016/j.snb.2017.01.166 CrossRefGoogle Scholar
- 5.Gao WL, Zhou YM, Xu CG, Guo MX, Qi ZC, Peng XJ, Gao B (2019) Bright hydrophilic and organophilic fluorescence carbon dots: one-pot fabrication and multi-functional applications at visualized Au3+ detection in cell and white light-emitting devices. Sens Actuators B: Chem 281:905–911. https://doi.org/10.1016/j.snb.2018.11.024 CrossRefGoogle Scholar
- 8.Niu WJ, Li Y, Zhu RH, Shan D, Fan YR, Zhang XJ (2015) Ethylenediamine-assisted hydrothermal synthesis of nitrogen-doped carbon quantum dots as fluorescent probes for sensitive biosensing and bioimaging. Sens Actuator B-Chem 218:229–236. https://doi.org/10.1016/j.snb.2015.05.006 CrossRefGoogle Scholar
- 15.Xu JJ, Yu CF, Feng T, Liu MY, Li FT, Wang Y, Xu JJ (2018) N-Carbamoylmaleimide-treated carbon dots: stabilizing the electrochemical intermediate and extending it for the ultrasensitive detection of organophosphate pesticides. Nanoscale 10:19390–19398. https://doi.org/10.1039/C8NR05098H CrossRefPubMedGoogle Scholar
- 21.Liu YS, Chen ZJ, Li W, Ma CH, Wu P, Wu XY, Li SJ, Liu SX (2018) A nanocomposite probe consisting of carbon quantum dots and phosphotungstic acid for fluorometric determination of chromate(VI) with improved selectivity. Microchim Acta 185(10):10–19. https://doi.org/10.1007/s00604-018-2993-1 CrossRefGoogle Scholar
- 22.Gong XJ, Liu Y, Yang ZH, Shuang SM, Zhang Z, Dong C (2017) An "on-off-on" fluorescent nanoprobe for recognition of chromium(VI) and ascorbic acid based on phosphorus/nitrogen dual-doped carbon quantum dot. Anal Chim Acta 968:85–96. https://doi.org/10.1016/j.aca.2017.02.038 CrossRefPubMedGoogle Scholar
- 30.Barberis A, Bazzu G, Calia G, Puggioni GM, Rocchitta GG, Migheli R, Schirra M, Desole MS, Serra PA (2010) New ultralow-cost telemetric system for a rapid electrochemical detection of vitamin C in fresh orange juice. Anal Chem 82(12):5134–5140. https://doi.org/10.1021/ac100303p CrossRefPubMedGoogle Scholar
- 33.Li LB, Wang C, Luo JX, Guo QW, Liu KY, Liu K, Zhao WJ, Lin YQ (2015) Fe3+-functionalized carbon quantum dots: A facile preparation strategy and detection for ascorbic acid in rat brain microdialysates. Talanta 144(1):1301–1307. https://doi.org/10.1016/j.talanta.2015.08.003 CrossRefPubMedGoogle Scholar
- 53.Gao YF, Jiao Y, Lu WJ, Liu Y, Han H, Gong XJ, Xian M, Shuang SM, Dong C (2018) Carbon dots with red emission as a fluorescent and colorimeteric dual-readout probe for the detection of chromium(VI) and cysteine and its logic gate operation. J Mater Chem B 6:6099–6107. https://doi.org/10.1039/C8TB01580E CrossRefGoogle Scholar
- 59.Meng HM, Zhang XB, Yang C, Kuai HL, Mao G, Gong L, Zhang W, Feng S, Chang J (2016) Efficient Two-Photon Fluorescence Nanoprobe for Turn-On Detection and Imaging of Ascorbic Acid in Living Cells and Tissues. Anal Chem 88(11):6057–6063. https://doi.org/10.1021/acs.analchem.6b01352 CrossRefPubMedGoogle Scholar