Opto-Electronic Properties of Green Synthesized ZnS Nanostructures

2018 ◽  
Vol 17 (04) ◽  
pp. 1760032
Author(s):  
Sujata Deb ◽  
P. K. Kalita ◽  
P. Datta
Keyword(s):  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Blue Shift ◽  
Cubic Phase ◽  
Capping Agent ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Green Capping Agent

ZnS nanostructures are synthesized by a wet chemical route using starch as green capping agent under nitrogen environment. The as-prepared nanostructures are characterized structurally, optically and electrically. X-ray diffraction (XRD) spectra confirm that the zinc sulfide (ZnS) nanoparticles have cubic phase (zinc blende). UV–Vis spectrum of the sample clearly shows that the absorption peak exhibits blue shift compared to their bulk counterpart, which confirms the quantum confinement effect of the nanostructures. Its photoluminescence (PL) spectrum shows near band gap emission at 392[Formula: see text]nm and extrinsic emission at 467[Formula: see text]nm. The particle sizes calculated from XRD and UV studies are in fair agreement with high resolution transmission electron microscopy (HRTEM) results. Starch is found to be a noble capping agent in bringing quantum confinement. The synthesis under nitrogen environment has been observed to produce quality products by reducing the oxide traces. Moreover, the I–V characteristics under dark and illumination show that ZnS can be more suitable as photodetector.

scholarly journals Optical Studies of Organically Functionalized Mn doped ZnS Quantum Dots

2021 ◽  
Vol 33 (12) ◽  
pp. 2972-2976
Author(s):  
Anju Bala ◽  
Rajeev Sehrawat ◽  
Renu Bala ◽  
Ashutosh Dixit
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement Effect ◽  
Emission Spectra ◽  
Blue Shift ◽  
Capping Agent ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Uv Visible ◽  
Mn Doped

Organically functionalized manganese doped zinc sulfide (ZnS/Mn) quantum dots were prepared by simple chemical method with polypyrrole (PPy) used as a capping agent. Prepared quantum dots were characterized with Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HR-TEM), X-ray diffraction microscope (XRD), UV-visible spectroscopy and photoluminescence spectroscopy. Crystalline size of PPy capped ZnS/Mn quantum dots for various concentrations of PPy were approximate 2 nm as analyzed by XRD and TEM analysis. The absorption spectra revealed the occurrence of a blue shift in the peak of absorption and an increase in the band gap value due to the quantum confinement effect. FTIR spectroscopy confirmed that shifting of broad peak at 2335.8 cm–1 was due to S-H stretching vibrations, which confirmed interaction of hydrogen and sulphur in ZnS/Mn/PPy nanocomposites. Uncapped ZnS/Mn and PPy capped ZnS/Mn quantum dots reveal the effective photoluminescence emission spectra in the range of 300-700 nm. With increase the value of capping agent in ZnS/Mn quantum dots, photoluminescence spectra going to red shifting. The photoluminescence properties of the organically functionalized ZnS nanoparticles are favourable for the application in optoelectronic devices.

Synthesis and Characterization of Mn2+ Doped ZnS Using Reverse Miceller Method

2014 ◽  
Vol 970 ◽  
pp. 283-287
Author(s):  
Rahizana Mohd Ibrahim ◽  
Markom Masturah ◽  
Huda Abdullah
Keyword(s):  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Blue Shift ◽  
Band Gap Energy ◽  
Confinement Effect ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Size Of Particles ◽  
Absorbance Spectra

In this work we synthesized the monodisperse of Zn1-xMnxS with x =0.00,0.02,0.04,0.06,0.08 and 0.10 nanoparticles by reverse micelle method using sodium bis (2-ethylhexyl) sulfosuccinate (AOT) as surfactant. The prepared particles were characterized using UV-Visible Spectroscopy, X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Photoluminescence (PL) for size, morphology and optical of the samples .UV-vis absorbance spectra for all of the synthesized nanoparticles show the maximum absorption for all samples is observed at range 210 - 300 nm . The absorption edge shifted to lower wavelengths when doping with ion Mn as per UV-Vis spectroscopy. The band gap energy values were increase from 4.50eV to 4.90 eV. This blue shift is attributed to the quantum confinement effect. The size of particles is found to be 3-5nm range. The Mn2+ doped ZnS nanoparticles using reverse micelles method shows the enhance of PL intensity results in monodisperse nanoparticles. Keywords: Nanoparticles; UV-vis absorbance spectra; quantum confinement effect; photoluminescence.

QUANTUM CONFINEMENT EFFECT IN HgTe NANOCRYSTALS AND VISIBLE LUMINESCENCE

2004 ◽  
Vol 03 (03) ◽  
pp. 393-401 ◽  
Author(s):  
S. RATH ◽  
A. K. DASH ◽  
S. N. SAHU ◽  
S. NOZAKI
Keyword(s):  
Valence Band ◽  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Free Exciton ◽  
Confinement Effect ◽  
Electrochemical Technique ◽  
Cubic Phase ◽  
Exciton Transition ◽  
Mercury Telluride ◽  
Transmission Electron

Mercury Telluride ( HgTe ) nanocrystals with a mean size of 5.35 nm have been synthesized by an electrochemical technique. Structural analysis by transmission electron microscopy and glancing angle X-ray diffraction studies indicate the presence of cubic phase HgTe nanocrystals in the deposit. Optical absorption measurements reveal two well resolved excitonic peaks around 578.5 nm and 550 nm attributed to heavy hole valence band (HVB)–conduction band (CB) and light hole valence band (LVB)–CB transitions, respectively, and suggest a band opening of bulk inverted narrow band gap HgTe as a result of strong quantum confinement effect (QCE). Visible photoluminescence (PL) of HgTe nanocrystals indicates free exciton transition around 579.5 nm as observed from the PL measurement at 300 K along with a bound exciton dominated band around 588 nm. Micro-Raman measurements at 300 K indicate the 1LO vibrational mode at 142.6 cm-1 shifted by 6 cm-1 from its standard bulk value and confirm the QCE.

Thiol-Capped CdSe and CdTe Nanoclusters: Synthesis by a Wet Chemical Route, Structural and Optical Properties

1998 ◽  
Vol 536 ◽  
Author(s):  
A. L. Rogach ◽  
A Eychmüller ◽  
J. Rockenberger ◽  
A. Kornowski ◽  
H. Weller ◽  
...  
Keyword(s):  
Particle Size ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Chemical Route ◽  
X Ray ◽  
Stabilizing Agents ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Wet Chemical Route ◽  
X Ray Absorption

AbstractCdSe and CdTe nanoclusters were formed in aqueous solutions at moderate temperatures by a wet chemical route in the presence of thiols as effective stabilizing agents. The nature of the stabilizing agent (thioalcohols or thioacids) had an important influence on the particle size and largely determined the photoluminescence properties. The nanoclusters were characterized by means of UV-vis absorption and photoluminescence spectroscopy, powder X-ray diffraction, high resolution transmission electron microscopy, and extended X-ray absorption fine structure measurements. CdSe and CdTe nanoclusters were crystalline, in the cubic zincblende phase, with mean sizes in the range of 2 to 5 nm depending on the preparative conditions and the postpreparative size-selective fractionation, and showed pronounced electronic transitions in the absorption spectra. Thioglycerol-stabilized CdTe nanoclusters possessed sharp band-egde photoluminescence being tunable with particle size.

Synthesis of Zn Doped CdSe Quantum Dots via Inverse Micelle Technique

2014 ◽  
Vol 807 ◽  
pp. 115-121 ◽  
Author(s):  
Fatihah Aplop ◽  
Mohd Rafie bin Johan
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement Effect ◽  
Blue Shift ◽  
X Ray Diffraction ◽  
Cdse Qds ◽  
Xrd Pattern ◽  
Transmission Electron ◽  
Inverse Micelle ◽  
Cadmium Selenide Quantum Dots ◽  
The Fourier Transform

Zinc doped Cadmium Selenide Quantum Dots (CdSe/Zn QDs) were synthesized via inverse micelle technique. The absorption spectra exhibit a strong blue-shift characteristic due to quantum confinement effect. The X-ray Diffraction (XRD) pattern showed the zinc-blende phase of Zn doped CdSe QDs. Transmission Electron Microscopy (TEM) images suggested that the sizes of QDs were falls in range between 2 – 8 nm, with narrow size distribution. The TEM images also revealed that the Zn doped CdSe QDs were spherical, having a compact and dense structure. The optical bandgap of Zn-doped CdSe QDs are smaller than the undoped CdSe QDs as shown in Tauc’s plot. The fourier transform infrared spectra proves the complexion of CdSe-Zn QDs.

Correlation Between Microstructure and Optical Properties of ZnO Based Nanostructures Grown by MOCVD

2008 ◽  
Vol 1074 ◽  
Author(s):  
Farid Falyouni ◽  
Julien Barjon ◽  
Vincent Sallet ◽  
Alain Lusson ◽  
Guy Garry ◽  
...  
Keyword(s):  
Low Temperature ◽  
Structural Properties ◽  
Quantum Confinement ◽  
Dopant Concentration ◽  
Quantum Confinement Effect ◽  
Chemical Vapor ◽  
Blue Shift ◽  
Transmission Electron ◽  
Optical Signature ◽  
Excitonic Emission

ABSTRACTThe correlation between structural properties of ZnO sharp conical needles grown by Metallorganic Chemical Vapor Deposition (MOCVD) on sapphire substrate and their optical signature measured by low temperature cathodoluminescence (CL) is investigated. Transmission Electron Microscopy (TEM) shows the excellent structural properties of these needles from their base up to the end of the tip. In order to probe the emission of the needles along their length, UV CL mapping has been performed at low temperature on a single needle previously characterized by TEM. A clear blue shift of 25meV is observed for the excitonic emission close to the needle tip. This shift is too high to be fully attributed to quantum confinement. Although, it qualitatively agrees with previous observations which assigned it to a surface contribution becoming dominant upon size shrinking, the effect is less pronounced. The results are discussed in term of surface quality and other possible contributions associated to a decrease of the n-dopant concentration and to quantum confinement effect close to the tip.

Growth and Optical Properties of SnO2 Ultra-Small Nanorods by the Novel Micelle Techniques

2008 ◽  
Vol 1087 ◽  
Author(s):  
Satchidananda Rath ◽  
Shinji Nozaki ◽  
Hiroshi Ono ◽  
Kazuo Uchida ◽  
Satoshi Khojima
Keyword(s):  
Quantum Confinement ◽  
Photoluminescence Spectrum ◽  
Tin Dioxide ◽  
Optical Band Gap ◽  
Quantum Confinement Effect ◽  
Average Diameter ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

AbstractTin-dioxide (SnO2) ultra-small nanorods (UNR) have been successfully synthesized using the novel micellar technique. From transmission electron microscopy, the average diameter and length of the UNRs are estimated to be 1.3 nm and 5.0 nm, respectively. The crystal structure of the SnO2 UNRs was found to be tetragonal from the glazing incidence x-ray diffraction. The optical band gap estimated from the absorption spectrum is blue-shifted by 1 eV from that of bulk (3.64 eV). The photoluminescence spectrum shows two groups of peaks each with several fine peaks, one in the wavelength range of 270 – 370 nm and the other in the range of 380 – 500 nm which are due to the strong quantum confinement effect.

SIZE-DEPENDENT PHOTOLUMINESCENCE AND ELECTROLUMINESCENCE OF COLLOIDAL CdSe QUANTUM DOTS

2013 ◽  
Vol 12 (02) ◽  
pp. 1350013 ◽  
Author(s):  
S. C. DEY ◽  
S. S. NATH
Keyword(s):  
Quantum Dots ◽  
Blue Shift ◽  
Diffraction Spectrum ◽  
Cdse Quantum Dots ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
X Ray ◽  
Light Emitting Devices ◽  
Transmission Electron ◽  
Vis Spectroscopy

Here we adopt a convenient green chemical route for synthesis of CdSe quantum dots, their characterization by UV/Vis absorption spectroscopy, X-ray diffraction study and transmission electron microscopy. We carry out photoluminescence and electroluminescence spectroscopy to investigate the variation in electro-optical property with size. By UV/Vis spectroscopy, blue shift is revealed and bandgap is also calculated. X-ray diffraction spectrum reveals cubic structure and transmission electron micrographs show quantum dots of different size distributions (in the range 2–8 nm). Both the luminescence spectroscopies reveal green-orange luminescence depending upon the size distribution and indicate the possibility of using CdSe quantum dots as light emitting devices with better compatibility and faster response.

scholarly journals Quantum Confinement in GaP Nanoclusters

1994 ◽  
Vol 351 ◽  
Author(s):  
Bernhard K. Laurich ◽  
David C. Smith ◽  
Matthew D. Healy
Keyword(s):  
Quantum Confinement ◽  
Cluster Size ◽  
Blue Shift ◽  
X Ray Diffraction ◽  
High Crystalline Quality ◽  
Lattice Contraction ◽  
X Ray ◽  
Transmission Electron ◽  
Bulk Absorption ◽  
Distinct Line

ABSTRACTWe have prepared GaP and GaAs nanoclusters from organometallic condensation reactions of E[Si(CH3)3]3 (E = P, As) and GaCl3. The size of the as synthesized clusters is 10 Å to 15 Å. Larger clusters of 20 Å to 30 Å size were obtained by thermal annealing of the as grown material. X-ray diffraction and transmission electron microscopy confirm the high crystalline quality. A lattice contraction of 6.7% could be seen for 10 Å sized GaAs clusters. The clusters are nearly spherical in shape. Optical absorption spectra show a distinct line which can be assigned to the fundamental transition of the quantum confined electronic state. The measured blue shift, with respect to the GaP bulk absorption edge is 0.53 eV. As the cluster is smaller than the exciton radius, we can calculate the cluster size from this blue shift and obtain 20.2 Å, consistent with the results from X-ray diffraction of 19.5 Å for the same sample.

[ZnSe(dbn)1/2] and [ZnSe(hda)1/2]: Two New Members of Inorganic-Organic Hybrid Semiconductor Nanocomposites Exhibiting A Strong Quantum Confinement Effect

2002 ◽  
Vol 728 ◽  
Author(s):  
Xiaoying Huang ◽  
Jing Li
Keyword(s):  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Diffraction Method ◽  
Blue Shift ◽  
Confinement Effect ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
New Members ◽  
Organic Hybrid ◽  
Semiconductor Nanocomposites

AbstractTwo new inorganic-organic hybrid II-VI semiconductor nanostructures have been synthesized by solvothermal reactions. These nanostructures consist of inorganic 2∞[ZnSe] layers and organic bridging diamine molecules as spacers. The crystal structures of [ZnSe(dbn)1/2](1, dbn = 1,4-diaminobutane) and [ZnSe(hda)1/2](2, hda = 1,6-hexanediamine) have been determined by the powder X-ray diffraction method. They are isostructural and crystallize in the orthorhombic crystal system, space group Pbca(No.62), Z = 4. Crystal data for 1: a = 6.646(3), b = 6.473(3), c = 22.31(1) Å, V = 961.2(13) Å3, for 2: a = 6.6252(18), b = 6.4505(17), c = 27.138(7) Å, V = 1159.8(9) Å3. The optical absorption experiments show that both 1 and 2 generate a very large blue shift in the absorption edge (1.5-1.6 eV) due to a strong quantum confinement effect (QCE). Thermogravimetric behavior of both compounds has also been investigated.

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