scholarly journals Polycation-Capped CdS Quantum Dots Synthesized in Reverse Microemulsions

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Karina Lemke ◽  
Joachim Koetz
Keyword(s):  
Quantum Dots ◽  
Electrostatic Interactions ◽  
Sodium Dodecyl ◽  
Cds Nanoparticles ◽  
Cds Quantum Dots ◽  
Fluorescence Measurements ◽  
Surfactant Interactions ◽  
Reverse Microemulsions ◽  
Different Types ◽  
Nanoparticle Aggregates

This paper is focused on the formation and recovery of cadmium sulfide (CdS) nanoparticles in two different types of polycation-modified reverse microemulsions using low molecular weight poly(diallyldimethylammonium chloride) (PDADMAC) and poly(ethyleneimine) (PEI). Both polymers were incorporated in a quaternary w/o microemulsion consisting of water, toluene-pentanol (1 : 1), and sodium dodecyl sulfate (SDS), as well as in a ternary w/o microemulsion consisting of water, heptanol, and 3-(N,N-dimethyl-dodecylammonio)-propanesulfonate (SB). UV-vis and fluorescence measurements in the microemulsion illustrate the capping effect of the polycations on the formation of the CdS quantum dots. The nanoparticles are redispersed in water and characterized by using UV-vis and fluorescence spectroscopy, in combination with dynamic light scattering. From the quaternary microemulsion, only nanoparticle aggregates of about 100 nm can be redispersed, but, from the ternary microemulsion, well-stabilized polycation-capped CdS quantum dots can be obtained. The results show that the electrostatic interactions between the polycation and the surfactant are of high relevance especially in the solvent evaporation and redispersion process. That means only that in the case of moderate polycation-surfactant interactions a redispersion of the polymer-capped CdS quantum dots without problems of aggregation is possible.

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.

Fluorescence Measurements and AFM Imaging of Bacteriorhodopsin Coupled with CdSe Quantum Dots for Optoelectronic Applications

2009 ◽  
Vol 1237 ◽  
Author(s):  
Nicolas Bouchonville ◽  
Michael Molinari ◽  
Alyona Sukhanova ◽  
Michel Troyon ◽  
Igor Nabiev
Keyword(s):  
Quantum Dots ◽  
Energy Transfer ◽  
Data Storage ◽  
Electrostatic Interactions ◽  
Optical Switching ◽  
Dominant Role ◽  
Resonance Energy ◽  
Functional Materials ◽  
Surface Charges ◽  
Fluorescence Measurements

AbstractA new nanohybrid material with a potential impact on energy transfer processes in biomolecules was developed by coupling colloidal fluorescent semiconductor CdSe/ZnS quantum dots (QDs) with a photochromic membrane protein, the bacteriorhodopsin (bR). The interactions between the nanocrystals and the proteins were studied by fluorescence spectroscopy and atomic force microscopy (AFM) measurements. A quenching in the photoluminescence (PL) of QDs emitting in the range of the bR absorption suggests a fluorescence resonance energy transfer effect from QDs (donors) to bR (acceptor). As the quenching evolution is different with the surface charges of the QDs, it suggests that the QDs interact with bR through electrostatic interactions. The AFM images of bR coupled with QDs capped with positive or negative surface groups confirm that the electrostatic interactions between QDs and bR play a dominant role in the way they are coupling together. The observed interactions between QDs and bR can provide the basis for the development of novel functional materials with unique photonic properties and having applications in the all-optical switching, photovoltaics and data storage.

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.

Design of CdS Quantum Dots / Multi-Walled Carbon Nanotubes Hybrid Structures for Photovoltaic Applications

2011 ◽  
Vol 1359 ◽  
Author(s):  
Fayna Mammeri ◽  
Andrea Ballarin ◽  
Marion Giraud ◽  
Lydie Vivet ◽  
Frederic Herbst ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Quantum Dots ◽  
Hybrid Structures ◽  
Cds Nanoparticles ◽  
Diazonium Salts ◽  
Thiol Groups ◽  
Cds Quantum Dots ◽  
Photovoltaic Applications ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

ABSTRACTThis paper presents the preparation of multi-walled carbone nanotubes (CNTs) and CdS nanoparticles based hybrid materials. We aim at comparing two kinds of CNTs’ functionalization by thiol groups in order to demonstrate that the surface chemistry done on the CNTs can direct the morphology of the nanohybrids. Indeed, strong oxidation of CNTs leads to shorter nanotubes opened at their ends, allowing the grafting of mercaptotriethoxysilane whereas the generation of diazonium salts in presence of pristine nanotubes should lead to the functionalization of the whole lateral surface of the nanotubes. CdS nanoparticles can then be anchored to thiol groups, leading to interesting hybrid precursors for photovoltaic applications.

scholarly journals APPLICATION OF LUMINESCENCE AND ABSORPTION SPECTRA TO CONTROL THE FORMATION OF A HETEROJUNCTION IN NANOSTRUCTURED RUTILE FILMS SENSITIZED BY CDS QUANTUM DOTS

2019 ◽  
Vol 21 (3) ◽  
pp. 399-405
Author(s):  
Sergei B. Kuschev ◽  
Liana Yu. Leonova ◽  
Anatoly N. Latyshev ◽  
Oleg V. Ovchinnikov ◽  
Elena V. Popova
Keyword(s):  
Quantum Dots ◽  
Absorption Spectra ◽  
Solid Phase ◽  
High Energy ◽  
Cds Nanoparticles ◽  
Energy Structure ◽  
Xenon Lamp ◽  
Cds Quantum Dots ◽  
Cds Nanocrystals ◽  
Thin Fi Lm

The effect of photon processing (FO) on the formation of a heterojunction in the TiO2/QD’sCdS interface obtained by applying separately synthesized CdS quantum dots to the TiO2 film in the rutile phase has been studied. The changes of luminescence spectra and absorption of the investigated samples after this treatment discovered. It is shown that the separation of charge carriers occurs only after irradiation of samples with a powerful light pulse of a xenon lamp.   REFERENCES Kapilashrami M., Zhang Y. , Liu Y.-S., Hagfeldt A., Guo J. Probing the Optical Property and Electronic Structure of TiO2 Nanomaterials for Renewable Ener gy Applications. Chem. Rev., 2014, v. 114, pp. 9662–9707.  https://doi.org/10.1021/cr5000893 Dang T. C., Pham D. L., Le H. C., Pham V. H. TiO2/CdS nanocomposite fi lms: fabrication, characterization, electronic and optical properties. Adv. Nat. Sci. Nanosci. Nanotechnol., 2010, v. 1, p. 015002. https://doi.org/10.1088/2043-6254/1/1/015002 Qian X., Qin D., Bai Y., Li T., Tang X., Wang E., Dong S., Photosensitization of TiO2 nanoparticulate thin fi lm electrodes by CdS nanoparticles. J. Solid State Electrochem., 2001, v. 5, pp. 562–567. https://doi.org/10.1007/s100080000179 Baker D. R., Kamat P. V. Photosensitization of TiO2 nanostructures with CdS quantum dots: Particulateversus tubular support architectures. Adv. Funct. Mater., 2009, v. 19, pp. 805–811. https://doi.org/10.1002/adfm.200801173 Cheng S., Fu W., Yang H., Zhang L., Ma J., Zhao H., Sun M., Yang L. Photoelectrochemical performance of multiple semiconductors (CdS/CdSe/ZnS) cosensitized TiO2 photoelectrodes. J. Phys. Chem. C, 2012, v. 116, pp. 2615–2621. https://doi.org/10.1021/jp209258r Khlyap H. Physics and technology of semiconductor thin fi lm-based active elements and devices. Bentham Science Publisher, 2012. https://doi.org/10.2174/97816080502151090101 Milnes A. G., Feucht D. L. Hetero junctions and metal-semiconductor junctions. Academic Press, 418 p. https://doi.org/10.1016/B978-0-12-498050-1.X5001-6 Ievlev V. M., Latyshev A. N., Kovneristyi Y. K., Turaeva T. L., Vavilova V. V., Ovchinnikov O. V., Selivanov V. N., Serbin O. V. Mechanism of the photonic activation of solid-phase processes. High Energy Chem., 2005, v. 39, pp. 397–402. https://doi.org/10.1007/s10733-005-0078-2 Ievlev V. M., Kushchev S. B., Latyshev A. N., Ovchinnikov O. V., Leonova L. Y, Solntsev K. A., Soldatenko S. A., Smirnov M. S., Sinelnikov A. A., Vozgorkov A. M., Ivikova M. A. Relation of absorption band edge of rutile fi lms and their structure. Inorg. Mater. Appl. Res., 2014, v. 5, pp. 14–21. https://doi.org/10.1134/s2075113314010055 Korolev N. V., Smirnov M. S., Ovchinnikov O. V, Shatskikh T.S. Energy structure and absorption spectra of colloidal CdS nanocrystals in gelatin matrix. Phys. E Low-Dimensional Syst. Nanostructures, 2015, v. 68, pp. 159–163. https://doi.org/10.1016/j.physe.2014.10.042. Ghazzal M. N., Wojcieszak R., Raj G., Gaigneaux E.M. Study of mesoporous cds-quantumdot-sensitized TiO2 fi lms by using x-ray photoelectron spectroscopy and afm. Beilstein J. Nanotechnol, 2014, v. 5, pp. 68–76. https://doi.org/10.3762/bjnano.5.6 Ahire R. R., Sagade A. A., Deshpande N. G., Chavhan S. D., Sharma R., Singh F. Engineering of nanocrystalline cadmium sulfi de thin fi lms by using swift heavy ions. J. Phys. D. Appl. Phys., 2007, v. 40, pp. 4850–4854. https://doi.org/10.1088/0022-3727/40/16/014 Ekimov A., Onushchenko A.A. Size quantization of the electron energy spectrum in a microscopic semiconductor crystal. JETP Lett., 1984, v. 40, pp. 1136–1139. Rolo A. G., Stepikhova M. V., Filonovich S. A., Ricolleau C., Vasilevskiy M. I., Gomes M. J. M. Microstructure and photoluminescence of CdS-doped silica fi lms grown by RF magnetron sputtering. Phys. Status Solidi Basic Res., 2002, v. 232, pp. 44–49. https://doi.org/10.1002/1521-3951(200207)232:1<44::AIDPSSB44> 3.0.CO;2-4 Smyntyna V., Skobeeva V., Malushin N. The nature of emission centers in CdS nanocrystals, Radiat. Meas., 2007, v. 42, pp. 693–696. https://doi.org/10.1016/j.radmeas.2007.01.068 Ehemba A. K., Socé M. M., Domingo J. J., Cisse S., Dieng M. Optimization of the properties of the back surface fi eld of a Cu (In, Ga) Se2 thin fi lm solar cell. American Journal of Energy Research, 2017, v. 5(2), pp. 57–62. https://doi.org/10.12691/ajer-5-2-5  

scholarly journals Potentiometric Study of Carbon Nanotube/Surfactant Interactions by Ion-Selective Electrodes. Driving Forces in the Adsorption and Dispersion Processes

2021 ◽  
Vol 22 (2) ◽  
pp. 826
Author(s):  
Francisco José Ostos ◽  
José Antonio Lebrón ◽  
María Luisa Moyá ◽  
Eva Bernal ◽  
Ana Flores ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrostatic Interactions ◽  
Adsorption Process ◽  
Driving Forces ◽  
Hydrophobic Interactions ◽  
Sodium Dodecyl ◽  
Tail Length ◽  
Ammonium Bromide ◽  
Ion Selective Electrodes ◽  
Surfactant Interactions

The interaction (adsorption process) of commercial ionic surfactants with non-functionalized and functionalized carbon nanotubes (CNTs) has been studied by potentiometric measurements based on the use of ion-selective electrodes. The goal of this work was to investigate the role of the CNTs’ charge and structure in the CNT/surfactant interactions. Non-functionalized single- (SWCNT) and multi-walled carbon nanotubes (MWCNT), and amine functionalized SWCNT were used. The influence of the surfactant architecture on the CNT/surfactant interactions was also studied. Surfactants with different charge and hydrophobic tail length (sodium dodecyl sulfate (SDS), octyltrimethyl ammonium bromide (OTAB), dodecyltrimethyl ammonium bromide (DoTAB) and hexadecyltrimethyl ammonium bromide (CTAB)) were studied. According to the results, the adsorption process shows a cooperative character, with the hydrophobic interaction contribution playing a key role. This is made evident by the correlation between the free surfactant concentration (at a fixed [CNT]) and the critical micellar concentration, cmc, found for all the CNTs and surfactants investigated. The electrostatic interactions mainly determine the CNT dispersion, although hydrophobic interactions also contribute to this process.

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).

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