CVD Assisted Hydrophobic Graphene Quantum Dots: Fluorescence Sensor for Aromatic Amino Acids

Abstract

In this paper, an hydrophobic graphene quantum dots(h‐GQDs) based PL sensor was demonstrated which can distinguish between aromatic and non‐aromatic amino acids. The h‐GQDSs prepared using Chemical Vapour Deposition method from acetylene gas and hydrogen gas was used as cocatalyst. The characterization of h‐GQDs was carried out by UV‐Visible absorption spectrophotometer, Dynamic Light Scattering, Scanning Electron Microscopy, Fourier Transform Infrared Spectrophotometer, Raman spectroscopy. These CVD assisted h‐GQDs form stable dispersion in organic solvents and are hydrophobic in nature. It was observed that photoluminescence (PL) intensity of h‐GQDs systems in the presence of aromatic amino acids is enhanced due to electron transfer from aromatic amino acids to h‐GQDs whereas with non‐aromatic amino acids PL intensity is quenched. Hence h‐GQDs systems can selectively distinguish between aromatic and non‐aromatic amino acid. The mechanistic insight is also discussed in the paper. Besides fluorescence sensors for aromatic amino acids, the h‐GQDs system can also be used as a fluorescence hydrophobic coating material as when coated on glass substrate it shows very high contact angle (107°).

Chiral carbon dots and their effect on the optical properties of photosensitizers

“…As-prepared L-CD-Ala, L-CD-Meth, and D-CD-Glc show excitation-dependent PL properties, as shown by other carbon dots and GQDs reported earlier. 32,33 The origin of excitation-dependent or excitation-independent PL properties has led to many hypotheses, from particle size distribution to the presence of different emissive states and solvent relaxation around CDs, and the participation of discrete multiple electronic states in the carbon dot system. 34 The emission maxima for L-CD-Ala, L-CD-Meth and D-CD-GLC are at wavelengths of 320 nm, 300 nm, and 320 nm, respectively.…”

Synthesis of graphene quantum dots and their applications in drug delivery

“…For example, Deka et al [31] prepared a PL sensor based on hydrophobic graphene quantum dots (h-GQDs) using acetylene and hydrogen as raw materials by CVD, which can distinguish aromatic and non-aromatic amino acids ( Fig. 6).…”

“…6 Schematic representation of the strategy employed to synthesize h-GQDs and fabrication it as a sensing system which can distinguish between aromatic and non-aromatic amino acids (reprinted/reproduced with the permission of Ref. [ 31 ], copyright 2017, ChemistrySelect) …”

“…There are many methods for GQDs synthesis based on top-down processes, including chemical oxidation method [24][25][26], hydrothermal method [27,28], ultrasonic assisted method [29], electrochemical oxidation method [30], chemical vapor deposition (CVD) method [31][32][33], and pulsed laser ablation (PLA) technique [34][35][36][37], or a combination of the above different approaches [38].…”

Carbon dots derived from water hyacinth and their application as a sensor for pretilachlor

“…On the other hand broad, XRD peaks near 24 0 are observedwhich suggest the amorphous nature of the prepared CDs [26]. Thus the crystallinity of the water hyacinth is diminished after the formation of CDs.The TEM images and corresponding size distribution curve of the CDs are also investigated and shown in Fig.4D, and E. The sizes of the CDs are found to below 10 nm and shows homogeneous size distribution.…”