Synthesis and Photoluminescence of ZnS Quantum Dots

2008 ◽  
Vol 8 (3) ◽  
pp. 1312-1315 ◽  
Author(s):  
Yu Hua Wang ◽  
Zhong Chen ◽  
Xiao Qun Zhou
Keyword(s):  
Quantum Dots ◽  
Ph Value ◽  
Broad Band ◽  
Surface States ◽  
Average Diameter ◽  
Zinc Sulphide ◽  
Photoluminescence Properties ◽  
Strong Broad Band ◽  
Zinc Blende ◽  
Transmission Electron

Single-phase zinc sulphide (ZnS) quantum dots were synthesized by a chemical method. The influence of the pH value of the Zn(CH3COO)2 solution on the size and photoluminescence properties of the ZnS quantum dots was evaluated. X-ray power diffraction, transmission electron microscopy, and ultraviolet-visible spectroscopy were used to characterize the structure, size, surface states, and photoluminescence properties of ZnS quantum dots. The results showed that the crystal structure of ZnS quantum dots was a cubic zinc blende structure, and their average diameter was about 3.0 nm. ZnS quantum dots with good distribution and high purity were obtained. A strong broad band centered at about 320 nm was observed in the excitation spectrum of ZnS quantum dots. Their emission spectrum peaking at about 408 nm, was due mostly to the trap-state emission. The relative integrated emission intensity of ZnS quantum dots decreased as the pH value of the Zn(CH3COO)2 solution increased, which could be ascribed to the increase in average diameter of the ZnS quantum dots as the pH value of Zn(CH3COO)2 solution increased.

Synthesis and Characterization of Water-Soluble Cu2+-Doped ZnSe Quantum Dots

2009 ◽  
Vol 79-82 ◽  
pp. 2043-2046 ◽  
Author(s):  
Shan Shan Li ◽  
Fu Tian Liu ◽  
Qun Wang ◽  
Xiu Xiu Chen ◽  
Ping Yang
Keyword(s):  
Quantum Dots ◽  
Green Emission ◽  
Average Diameter ◽  
Water Soluble ◽  
X Ray ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Uv Excitation ◽  
Zinc Blende Structure

Cu2+-doped ZnSe quantum dots (ZnSe:Cu) were prepared via a green and simple route, namely the chemical coprecipitation method. Under 365 nm UV excitation, green emission is observed. X-ray powder diffraction (XRD) shows that ZnSe:Cu nanoparticle is cubic zinc blende structure; the transmission electron microscopy (TEM) exhibits that the average diameter of ZnSe:Cu nanocrystals is less than 10 nm. UV-vis spectrophotometer and fluorescence spectrophotometer indicate that ZnSe:Cu nanocrystals have good fluorescence effects.

ENHANCED UV EMISSION IN YTTRIUM-DOPED ZnS NANOPARTICLES SYNTHESIZED BY PRECIPITATION METHOD

2018 ◽  
Vol 25 (03) ◽  
pp. 1850063 ◽  
Author(s):  
NACHIMUTHU SUGANTHI ◽  
KUPPUSAMY PUSHPANATHAN
Keyword(s):  
Spherical Shape ◽  
Zinc Sulphide ◽  
Precipitation Method ◽  
Zns Nanoparticles ◽  
Ultraviolet Detector ◽  
Selected Area Electron Diffraction ◽  
Uv Emission ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Photoluminescence Studies

This paper deals with the effect of yttrium doping on the structural and optical properties of zinc sulphide (ZnS) nanoparticles with nanoparticulated mesoporous. The morphology of the nanoparticles is determined by FESEM and it shows that the particles are spherical shape. HRSEM images show that particle size and agglomerated nature of the samples are augmented when doping concentration increases. Transmission electron microscope images probe the spherical shape of the nanoparticles as well as small number of inter particle mesoporous with intra-particles. The selected area electron diffraction images validate the crystalline and cubic nature of the synthesized samples. The presence of intra-particles is corroborated by XRD and FTIR spectra. X-ray diffraction’s results also confirm that the synthesized nanoparticles are crystallized in zinc blende structure. The diffuse reflectance spectra indicate that 5[Formula: see text]wt.% of yttrium-doped zinc sulphide shows higher reflectance than the undoped ZnS. Thus photoluminescence studies suggest that 5[Formula: see text]wt.% of yttrium-doped ZnS sample may be used for the development of supersensitive ultraviolet detector.

Effect of L-Cysteine on Photoluminescence of Zns:F Quantum Dots

2018 ◽  
Vol 281 ◽  
pp. 716-722
Author(s):  
Xiao Xuan Wang ◽  
Shu Zhen Wang ◽  
Shu Wang Duo ◽  
Xing Yu Jiang ◽  
Wen Li Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Water Solubility ◽  
Luminescent Properties ◽  
Solid State Method ◽  
X Ray ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Structure Surface ◽  
State Method ◽  
Zinc Blende Structure

ZnS:F quantum dots (QDs) capping with and without L-cys were synthesized by a solid-state method at low temperature, and the influence of L-cys on the properties of ZnS:F QDs were investigated. The crystal structure, surface morphology and luminescent properties of the samples were analyzed by X-ray diffractometer (XRD), transmission electron microscope (TEM), fourier transform infrared (FTIR), photoluminescence spectrometer (PL) and ultraviolet-visible spectrometer (UV-Vis). The results showed that all samples had a zinc blende structure with particle size in the range of 2-6 nm. The emission intensity was significantly enhanced after capping with L-cys, and the strongest luminescence was obtained when the ratio of L-cys/ZnS:F was 0.8:1, and was about 2.5 times of that of ZnS:F QDs. The capping of L-cys increased the grain size of ZnS:F QDs and their water solubility.

Highly Luminescent Inverted ZnS/CdS Core/Shell Quantum Dots

2008 ◽  
Vol 8 (8) ◽  
pp. 3949-3954 ◽  
Author(s):  
Madhulika Sharma ◽  
D. Gupta ◽  
D. Kaushik ◽  
A. B. Sharma ◽  
R. K. Pandey
Keyword(s):  
Quantum Dots ◽  
Grazing Angle ◽  
Surface States ◽  
Shell Structures ◽  
Luminescence Spectroscopy ◽  
Core Shell ◽  
Additional Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Synthesis of highly luminescent and monochromatic inverted core–shell structures utilizing ZnS/CdS quantum dots (QDs) has been investigated. The core/shell quantum dots have been characterized using grazing angle X-ray diffraction (XRD), Transmission electron microscopy, Optical absorption and luminescence spectroscopy. The results suggested that passivation of surface states along with an increased localization of electron and hole in CdS shell layer, give rise to increased monochromaticity with higher quantum yield. The possibility of using the inverted core–shell structure as an additional parameter for tuning the color of luminescence has also been discussed.

Effect of Charge Transferring Materials on Photoluminescence Properties of CdSe/ZnS Quantum Dots

2014 ◽  
Vol 981 ◽  
pp. 879-882
Author(s):  
Xuan Lin Chen ◽  
Yu Qiu Qu ◽  
Gui Fan Li ◽  
Hong Wei ◽  
Liu Yang Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Absorption Spectrometry ◽  
Oxidation Potential ◽  
Dynamic Quenching ◽  
Photoluminescence Properties ◽  
Time Resolved ◽  
Transmission Electron ◽  
Quenching Efficiency ◽  
Quenching Process ◽  
Pl Quenching

The CdSe/ZnS core/shell quantum dots (QDs) were synthesized and characterized with absorption spectrometry, photoluminescence (PL) spectrometry and transmission electron microscopy. PL quenching of colloidal CdSe/ZnS QDs in the presence of charge transferring material was studied by means of steady-state and time-resolved PL spectroscopy. With increasing charge transferring materials concentration in the CdSe/ZnS QDs solution, the PL intensity and lifetime of CdSe/ZnS QDs decrease gradually. The quenching efficiency of CdSe/ZnS QDs decrease with increasing the oxidation potential of charge transferring materials. Based on the analysis, there are two pathways in the PL quenching process: static quenching and dynamic quenching. The dynamic quenching is correlated with hole transfer from QDs to the charge transferring materials.

scholarly journals Synthesis and characterization of oleic acid stabilized CdTe quantum dots and their properties as luminescence quencher of a pyridine pendented rod-coil homopolymer

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Manpreet Kaur ◽  
Duryodhan Sahu
Keyword(s):  
Quantum Dots ◽  
Oleic Acid ◽  
Surface Passivation ◽  
Average Diameter ◽  
Cdte Quantum Dots ◽  
Aqueous Synthesis ◽  
Quenching Effect ◽  
Pl Spectra ◽  
Cdte Nanocrystals ◽  
Transmission Electron

AbstractWe report a facile one-step non aqueous synthesis of oleic acid stabilized cadmium telluride (CdTe) quantum dots (QDs) with an average diameter of 3 nm to 4 nm by hot injection method. The synthesized oleic acid capped QDs observed by TEM were nearly spherical. The optical properties of QDs were characterized by UV-Vis absorption spectra and photoluminescence (PL) spectra. The structures of QDs and their surface passivation were further verified using transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The quenching effect of the CdTe QD was explored by addition of CdTe nanocrystals into a solution of rod-coil homopolymer (poly[10-(6-(9,9-diethyl-7-(pyridin-4-yl)-9H-fluoren-2-yl)naphthalen-2-yloxy) decyl methacrylate]) (PFNA) having pendent pyridine. The gradual addition of quantum dots to the solution of PFNA quenched the PL spectra of PFNA. This may be used to explore the coordination ability of pyridine containing homopolymer with CdTe quantum dots.

Optical Properties of Water-Soluble Er-Doped ZnS Quantum Dots Synthesized by a Hydrothermal Process

2013 ◽  
Vol 800 ◽  
pp. 402-405 ◽  
Author(s):  
Gang Li ◽  
Li Hua Li ◽  
Liu Shuan Yang ◽  
Jin Liang Huang
Keyword(s):  
Quantum Dots ◽  
Average Particle Size ◽  
Hydrothermal Process ◽  
Water Soluble ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Er Doped

Er3+:ZnS quantum dots(QDs) were synthesized by hydrothermal process. The structure, morphology and luminescence properties were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. It was found that the Er3+:ZnS QDs are zinc blende structure with an average particle size of about 8 nm. In PL spectra, The broad peak of ZnS NCs located at 400nm was commonly assigned to sulfur vacancies. The intensity of exciting peak and emission peak at of Er3+:ZnS QDs decreased with doping concentration increasing.

Phosphine-Free Synthesis and Photoluminescence Properties of ZnSe:Cu/ZnSe/ZnS Core/Shell Nanocrystals

2012 ◽  
Vol 549 ◽  
pp. 12-16 ◽  
Author(s):  
Jin Zhong Niu ◽  
Gui Min Tian ◽  
Li Li Zheng ◽  
Yong Guang Cheng ◽  
Shuang Mei Zhu ◽  
...  
Keyword(s):  
Emission Peak ◽  
Core Shell ◽  
Size Distributions ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Structures And Properties ◽  
Znse Nanocrystals

High quality zinc blende ZnSe nanocrystals were successfully synthesized using an environmentally friendierly phosphine-free method. Using pre-synthesized ZnSe nanocrystals as core to dope Cu2+ ions, we obtained ZnSe:Cu/ZnSe and ZnSe:Cu/ZnSe/ZnS core/shell nanocrystals. Absorption spectruscopy, photoluminescence (PL) spectruscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize the structures and properties of as-synthesized three kinds of nanocrystals. The results demonstrated that nanocrystals had well dispersion and narrow size-distributions, and the PL emission peak of as-synthesized ZnSe:Cu/ZnSe/ZnS core/shell nanocrystals could be easily tuned from 480 nm to 520 nm by using different sized ZnSe cores.

Optical Properties of Zigzag Twinned Geometry of Zn2SnO4 Nanowires

2007 ◽  
Vol 7 (2) ◽  
pp. 486-489 ◽  
Author(s):  
Sathyaharish Jeedigunta ◽  
Manoj K. Singh ◽  
Ashok Kumar ◽  
M. Shamsuzzoha
Keyword(s):  
Green Emission ◽  
Average Diameter ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Photoluminescence Properties ◽  
Thermal Evaporation Method ◽  
Green Emission Band ◽  
Uv Emission ◽  
Transmission Electron ◽  
Weak Peak

High-density single-crystalline Zn2SnO4 nanowires have been successfully synthesized by using a simple thermal evaporation method by heating a mixture of ZnO and SnO2 nano powders. The products in general contain various geometries of wires, with an average diameter of 80–100 nm. These nanowires are ultra-long, up to 100 microns. The transmission electron microscopy study showed that these nanowires exhibited zigzag twinned geometry, and grow along the 〈111〉 direction. Low-temperature photoluminescence properties of the nanowires were measured, showing a strong green emission band at about 515 nm and a weak peak corresponding to UV emission at about 378 nm, which have not been reported before.

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