OPTICAL PROPERTIES OF CHEMICALLY PREPARED CdS QUANTUM DOTS IN POLYVINYL ALCOHOL

2009 ◽  
Vol 23 (04) ◽  
pp. 545-555 ◽  
Author(s):  
J. BARMAN ◽  
J. P. BORAH ◽  
K. C. SARMA
Keyword(s):  
Quantum Dots ◽  
Particle Size ◽  
Band Gap ◽  
Blue Shift ◽  
Cds Nanoparticles ◽  
Cds Quantum Dots ◽  
Chemical Route ◽  
Visible Absorption ◽  
Weak Band ◽  
Composite Band

Excitonic effects are observed in the optical absorption and photoluminescence of strongly confined CdS quantum dots embedded in the polymer matrix. CdS nanoparticles of different crystallite sizes have been prepared by chemical route with polymer as a host material. The CdS nanocomposite film was made up of particle smaller than 5 nm and shows a composite band gap up to 3.2 eV, whereas the band gap for bulk hexagonal CdS is about 2.42 eV. Photoluminescence spectra show a strong emission band corresponding to electron–hole recombination and a weak band due to defect emission. The decrease of particle size was monitored from the U-V visible absorption measurement as well as photoluminescence, which suffered blue shift with decrease in particle size. The particle size and surface morphology were also analyzed by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM).

scholarly journals Synthesis, Characterization and Photophysical Analysis of CDS Nanoparticles

2019 ◽  
Vol 9 (2S2) ◽  
pp. 720-725
Keyword(s):  
Quantum Dots ◽  
Particle Size ◽  
Steady State ◽  
Cds Nanoparticles ◽  
Cds Quantum Dots ◽  
Quenching Process ◽  
Triethyl Amine ◽  
Dimethyl Amine ◽  
Static Nature ◽  
State Luminescence

The CdS quantum dots are prepared in AOT reverse micellar self-assemblies. The quantum dots were prepared from different precursor ratios of 1:1 and 1:2 which yielded different particle size. Steady state luminescence quenching studies were carried out for these quantum dots with N, N-dimethyl amine and triethyl amine. The downward curvature was observed form the SternVolmer plots showing the static nature of the quenching process. The static nature is attributed to presence of the quencher molecules to the quantum dot surface.

BURSTEIN–MOSS SHIFT IN CdS NANOCRYSTALLITES SYNTHESIZED VIA AQUEOUS PRECIPITATION

2012 ◽  
Vol 11 (01) ◽  
pp. 1250003
Author(s):  
PUJA CHAWLA ◽  
S. P. LOCHAB ◽  
NAFA SINGH
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Aqueous Medium ◽  
Absorption Maximum ◽  
Chemical Precipitation ◽  
Cds Nanoparticles ◽  
Cds Quantum Dots ◽  
Excitonic Peak ◽  
Solid Form

We report here the UV-VIS study of CdS nanoparticles synthesized via Chemical precipitation in aqueous medium, the UV-VIS of CdS in aqueous medium shows an excitonic peak at 230 nm, while that of CdS quantum dots in solid form shows an absorption maximum at 480 nm. This bleaching of band gap may be attributed to Moss–Burstein shift in the absorbance edge.

Immobilized CdS quantum dots in spherical polyelectrolyte brushes: fabrication, characterization and optical properties

2015 ◽  
Vol 3 (15) ◽  
pp. 3745-3751 ◽  
Author(s):  
Yu Cang ◽  
Rui Zhang ◽  
Guixin Shi ◽  
Jianchao Zhang ◽  
Lixiao Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Cds Nanoparticles ◽  
Basic Solution ◽  
Cds Quantum Dots ◽  
Polyelectrolyte Brushes ◽  
Photochemical Stability ◽  
Spherical Polyelectrolyte Brushes

The SPB@CdS nanoparticles exhibit controllable and reversible photoluminescence with pH as a trigger and strong photochemical stability in basic solution.

scholarly journals Optical and Structural Properties of CdS Quantum Dots Synthesized Using (MW-CBD) Technique

2020 ◽  
pp. 44-52
Author(s):  
Ahmed Ahmed S. Abed ◽  
Sattar J. Kasim ◽  
Abbas F. Abbas
Keyword(s):  
Thin Films ◽  
Quantum Dots ◽  
Room Temperature ◽  
Energy Gap ◽  
Cds Nanoparticles ◽  
Cds Quantum Dots ◽  
Optical Energy Gap ◽  
Glass Substrates ◽  
High Adhesion ◽  
Uv Visible

In the present study, the microwave heating method was used to prepare cadmium sulfide quantum dots CdSQDs films. CdS nanoparticles size average obtained as (7nm). The morphology, structure and composition of prepared CdSQDs were examined using (FE-SEM), (XRD) and (EDX). Optical properties of CdSQDs thin films formed and deposited onto glass substrates have been studied at room temperature using UV/ Visible spectrophotometer within the wavelength of (300-800nm), and Photoluminescence (PL) spectrum. The optical energy gap (Eg) which estimated using Tauc relation was equal (2.6eV). Prepared CdS nanoparticles thin films are free from cracks, pinholes and have high adhesion to substrate.

Charge directed assembly of CdTe/CdS nanoparticles inside monocrystalline KH2PO4

CrystEngComm ◽  
2017 ◽  
Vol 19 (45) ◽  
pp. 6804-6810 ◽  
Author(s):  
D. Vorontsov ◽  
S. Filonenko ◽  
A. Kanak ◽  
G. Okrepka ◽  
Y. Khalavka
Keyword(s):  
Quantum Dots ◽  
Potassium Dihydrogen Phosphate ◽  
Directed Assembly ◽  
Cds Nanoparticles ◽  
Dihydrogen Phosphate ◽  
Cds Quantum Dots ◽  
Potassium Dihydrogen

The synthesis of aqueous CdTe/CdS quantum dots (QDs) embedded in potassium dihydrogen phosphate KH2PO4 (KDP) is demonstrated.

Morphology and Band Gap Modulation of CdS Quantum Dots Deposited on Reoxidation TiO2 Nanotube Arrays

2014 ◽  
Vol 6 (1) ◽  
pp. 171-177 ◽  
Author(s):  
Miao Zhang ◽  
Shiwei Shi ◽  
Gang He ◽  
Xueping Song ◽  
Zhaoqi Sun
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Nanotube Arrays ◽  
Cds Quantum Dots ◽  
Band Gap Modulation

Band Gap Modulation of Lead Sulfide QDs

NANO ◽  
2018 ◽  
Vol 13 (06) ◽  
pp. 1850060 ◽  
Author(s):  
Pengyu Zeng ◽  
Wei Li ◽  
Yun Zhao ◽  
Mengting Liu
Keyword(s):  
Quantum Dots ◽  
Particle Size ◽  
Optical Properties ◽  
Band Gap ◽  
Lead Sulfide ◽  
Optical Band Gap ◽  
Phase Method ◽  
Liquid Phase Method ◽  
Lead Sulfide Quantum Dots ◽  
Band Gap Modulation

Lead sulfide quantum dots (QDs) were prepared by liquid phase method. The particle size can be controlled by changing the concentration of reactants and surfactant and the size of the QDs varies from 7[Formula: see text]nm to 20[Formula: see text]nm, which results in the change of the optical properties and the band gap of the particles. The optical band gap of lead sulfide QDs increased drastically with the decrease of the diameter of the sample QDs.

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