Facile one-step sonochemical synthesis of AgCl quantum dots with enhanced photocatalytic activity and its size effects

2020 ◽  
Vol 13 (06) ◽  
pp. 2051036
Author(s):  
Junjie Zhang ◽  
Hujiabudula Maimaitizi ◽  
Tao Zhang ◽  
Yalkunjan Tursun ◽  
Dilinuer Talifu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Photocatalytic Activity ◽  
Band Gap ◽  
Size Effects ◽  
Ultrasonic Method ◽  
Energy Levels ◽  
Average Diameter ◽  
Light Illumination ◽  
Quantum Size ◽  
One Step

In this work, a facile ultrasonic method for the fabrication of AgCl quantum dots (AgCl QDs) with an average diameter of about 2.5[Formula: see text]nm was reported for the first time. The material was analyzed by various techniques. In addition, effects of material’s size on its photocatalytic activities were studied. Results suggested that the AgCl QDs exhibited excellent photocatalytic activity to degrade Rhodamine B (RhB) and tetracycline (TC) under visible light illumination, and the degradation rate of RhB (TC) had reached up to 96.6% (72.2%) in 20 min, which was higher than that of AgCl nanoparticles (23[Formula: see text]nm) and AgCl nanospheres (114[Formula: see text]nm), respectively. Besides, the band gap of the material was increased when the size of material decreased from 23[Formula: see text]nm to 2.5[Formula: see text]nm. The significantly improved photocatalytic performance and increased band gap of AgCl QDs were mainly related to the quantum size effects of AgCl, which results in the more electron fluctuation in quantized energy levels and the lower recombination of electrons and holes.

QUANTUM SIZE EFFECTS ON THE ENERGY LEVELS AND FAR-INFRARED SPECTRA: CHANGES FROM QUANTUM DOTS TO QUANTUM RINGS

2007 ◽  
Vol 21 (27) ◽  
pp. 4715-4724
Author(s):  
HUI PAN
Keyword(s):  
Quantum Dots ◽  
Infrared Spectra ◽  
Size Effects ◽  
Energy Levels ◽  
Far Infrared ◽  
Electron Interaction ◽  
Quantum Size Effects ◽  
Quantum Rings ◽  
Quantum Size ◽  
Far Infrared Spectra

The energy levels and far-infrared spectra of two electrons confined in quantum dots and quantum rings under a magnetic field have been investigated. The size and shape effects of quantum rings on the levels and the spectra are clearly revealed. It is found that the spin oscillation of two electrons in a quantum ring with a magnetic field is caused by the Coulomb interaction. The transitions of two-electron far-infrared spectra are clearly shown from quantum dots to quantum rings. The influence of electron–electron interaction on the energy levels and far-infrared spectra has been discussed. The quantum size effects predict a possibility to observe phenomena related to electron-electron interaction in quantum rings.

Quantum dots in photocatalytic applications: efficiently enhancing visible light photocatalytic activity by integrating CdO quantum dots as sensitizers

2017 ◽  
Vol 19 (36) ◽  
pp. 24915-24927 ◽  
Author(s):  
A. H. Reshak
Keyword(s):  
Quantum Dots ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Photocatalytic Performance ◽  
Optical Band Gap ◽  
Visible Light Active ◽  
Photocatalytic Applications ◽  
Visible Light Photocatalytic

The amalgamation of a wide optical band gap photocatalyst with visible-light-active CdO quantum dots (QDs) as sensitizers is one of the most efficient ways to improve photocatalytic performance under visible light irradiation.

scholarly journals One-Step Synthesis of Diamine-Functionalized Graphene Quantum Dots from Graphene Oxide and Their Chelating and Antioxidant Activities

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 104 ◽  
Author(s):  
Rabeb El-Hnayn ◽  
Laetitia Canabady-Rochelle ◽  
Christophe Desmarets ◽  
Lavinia Balan ◽  
Hervé Rinnert ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Colloidal Stability ◽  
Antioxidant Activities ◽  
Graphene Quantum Dots ◽  
Average Diameter ◽  
Functionalized Graphene ◽  
One Step ◽  
Low Cytotoxicity ◽  
Health Applications

2,2’-(Ethylenedioxy)bis(ethylamine)-functionalized graphene quantum dots (GQDs) were prepared under mild conditions from graphene oxide (GO) via oxidative fragmentation. The as-prepared GQDs have an average diameter of ca. 4 nm, possess good colloidal stability, and emit strong green-yellow light with a photoluminescence (PL) quantum yield of 22% upon excitation at 375 nm. We also demonstrated that the GQDs exhibit high photostability and the PL intensity is poorly affected while tuning the pH from 1 to 8. Finally, GQDs can be used to chelate Fe(II) and Cu(II) cations, scavenge radicals, and reduce Fe(III) into Fe(II). These chelating and reducing properties that associate to the low cytotoxicity of GQDs show that these nanoparticles are of high interest as antioxidants for health applications.

Electronic structure of on- and off-center hydrogenic impurities in quantum dots and quantum nanowires: energies and dipole polarizability

2018 ◽  
Vol 96 (10) ◽  
pp. 1104-1115 ◽  
Author(s):  
R.L.M. Melono ◽  
D. Dobgima ◽  
O. Motapon
Keyword(s):  
Quantum Dots ◽  
Electric Dipole ◽  
Energy Levels ◽  
Model Potential ◽  
Binding Energies ◽  
Dipole Polarizability ◽  
Cavity Radius ◽  
Quantum Size ◽  
Dipole Polarizabilities

The energy levels, ground state binding energies, and electric dipole polarizabilities of hydrogenic impurities in quantum dots and quantum nanowires have been investigated using a non-relativistic B-spline based variational method. Firstly, we have worked on the characterization of those impurities (donor/electron) in quantum dots and quantum nanowires, considering the two cases where the impurity is centered or off-centered in the nanostructure. Secondly, the electric dipole polarizabilities have been computed and their sensitivity with confinement parameters investigated. So the energies, binding energies, and dipole polarizabilities were reported for the centered and the off-centered donor and electron impurities as a function of the cavity radius and the off-center displacement. We found that the polarization of the studied system greatly depends on the model potential form, the off-center displacement, and the cavity radius. In the case of quantum dots and for the parabolic potential, the convergence of the polarizability for large values of the quantum size is shown. For the quantum nanowire case, we have shown that the polarizability is greater in the case of the z axis displacement than that of the transversal one. This leads to the fact that the system is more polarizable when the impurity is moved along the z axis than the transversal one.

Facile one-step synthesis of cerium oxide-carbon quantum dots/RGO nanohybrid catalyst and its enhanced photocatalytic activity

2017 ◽  
Vol 43 (3) ◽  
pp. 3072-3079 ◽  
Author(s):  
Ramanujam Kannan ◽  
Ae Rhan Kim ◽  
Seong Kug Eo ◽  
Seong Ho Kang ◽  
Dong Jin Yoo
Keyword(s):  
Quantum Dots ◽  
Photocatalytic Activity ◽  
Cerium Oxide ◽  
Carbon Quantum Dots ◽  
One Step

Quantum size effects on the optical band gap of microcrystalline Si:H

1988 ◽  
Vol 38 (8) ◽  
pp. 5726-5729 ◽  
Author(s):  
Shoji Furukawa ◽  
Tatsuro Miyasato
Keyword(s):  
Band Gap ◽  
Size Effects ◽  
Optical Band Gap ◽  
Quantum Size Effects ◽  
Quantum Size
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