Amorphous Carbon Dots and their Remarkable Ability to Detect 2,4,6-Trinitrophenol

Abstract

Apparently mundane, amorphous nanostructures of carbon have optical properties which are as exotic as their crystalline counterparts. In this work we demonstrate a simple and inexpensive mechano-chemical method to prepare bulk quantities of self-passivated, amorphous carbon dots. Like the graphene quantum dots, the water soluble, amorphous carbon dots too, exhibit excitation-dependent photoluminescence with very high quantum yield (~40%). The origin and nature of luminescence in these high entropy nanostructures are well understood in terms of the abundant surface traps. The photoluminescence property of these carbon dots is exploited to detect trace amounts of the nitro-aromatic explosive — 2,4,6-trinitrophenol (TNP). The benign nanostructures can selectively detect TNP over a wide range of concentrations (0.5 to 200 µM) simply by visual inspection, with a detection limit of 0.2 µM, and consequently outperform nearly all reported TNP sensor materials.

Sustainable Synthesis Processes for Carbon Dots through Response Surface Methodology and Artificial Neural Network.

“…The image clearly depicts the synthesized CDs as well dispersed in water with a spherr shown in Figure 7. The HrTEM provides a validation of the nano dimensions present in the synthesized CDs via hydrothermal route which is in agreement with semiconductors synthesized at the nano scale [35,36].…”

Green Synthesis of Highly Luminescent Carbon Quantum Dots from Lemon Juice

“…Carbohydrates in lemon juices usually contain fiber and sugars such as sucrose, fructose, and glucose. e scientists suggest that any carbohydrate containing C, H, and O in a ratio of 1 : 2 : 1 where C and O exist in the form that allows dehydration under hydrothermal conditions can be used to prepare C-dots [13].…”

Highly sensitive fluorometric method based on nitrogen-doped carbon dot clusters for tartrazine determination in cookies samples

“…Namely, the dopant nitrogen atoms were inserted in the defect area or the surface of the slightly graphitic structure. Figure 3d shows the O 1s spectra with a broad peak between 534.2 and 530.3 eV, which can be attributed to C=O/O-H and C-O [27]. Specifically, the peak centered at 532.3 eV resulted from the OH bond [23].…”

“…Specifically, the multicolor properties of amorphous CDs could be explained by abundant surface defects and high entropy states in amorphous nanostructures [27]. Figure 4c shows the excitation wavelength-dependent emission properties of the CDs.…”