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Fabrication and spectroscopic studies on highly luminescent CdSe/CdS nanorod polymer composites
Jana Bomm,Andreas Büchtemann,Angela Fiore,Liberato Manna
Beilstein Journal of Nanotechnology , 2010, DOI: 10.3762/bjnano.1.11
Abstract: Highly luminescent nanocomposites were prepared by incorporating CdSe/CdS core/shell nanorods into different polymer matrices. The resulting nanocomposites show high transparency of up to 93%. A photoluminescence quantum efficiency of 70% was obtained, with an optimum combination of nanorod (0.05 wt %) and at a UV-initiator concentration of 0.1 wt % for poly(lauryl methacrylate). Nanorods tend to agglomerate in cellulose triacetate.
Synthesis and application of luminescent single CdS quantum dot encapsulated silica nanoparticles directed for precision optical bioimaging
Veeranarayanan S, Poulose AC, Mohamed MS, Nagaoka Y, Iwai S, Nakagame Y, Kashiwada S, Yoshida Y, Maekawa T, Kumar DS
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S31310
Abstract: thesis and application of luminescent single CdS quantum dot encapsulated silica nanoparticles directed for precision optical bioimaging Original Research (3412) Total Article Views Authors: Veeranarayanan S, Poulose AC, Mohamed MS, Nagaoka Y, Iwai S, Nakagame Y, Kashiwada S, Yoshida Y, Maekawa T, Kumar DS Published Date July 2012 Volume 2012:7 Pages 3769 - 3786 DOI: http://dx.doi.org/10.2147/IJN.S31310 Received: 29 February 2012 Accepted: 28 April 2012 Published: 17 July 2012 Srivani Veeranarayanan, Aby Cheruvathoor Poulose, M Sheikh Mohamed, Yutaka Nagaoka, Seiki Iwai, Yuya Nakagame, Shosaku Kashiwada, Yasuhiko Yoshida, Toru Maekawa, D Sakthi Kumar Bio Nano Electronics Research Centre, Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, Japan Abstract: This paper presents the synthesis of aqueous cadmium sulfide (CdS) quantum dots (QDs) and silica-encapsulated CdS QDs by reverse microemulsion method and utilized as targeted bio-optical probes. We report the role of CdS as an efficient cell tag with fluorescence on par with previously documented cadmium telluride and cadmium selenide QDs, which have been considered to impart high levels of toxicity. In this study, the toxicity of bare QDs was efficiently quenched by encapsulating them in a biocompatible coat of silica. The toxicity profile and uptake of bare CdS QDs and silica-coated QDs, along with the CD31-labeled, silica-coated CdS QDs on human umbilical vein endothelial cells and glioma cells, were investigated. The effect of size, along with the time-dependent cellular uptake of the nanomaterials, has also been emphasized. Enhanced, high-specificity imaging toward endothelial cell lines in comparison with glioma cells was achieved with CD31 antibody-conjugated nanoparticles. The silica-coated nanomaterials exhibited excellent biocompatibility and greater photostability inside live cells, in addition to possessing an extended shelf life. In vivo biocompatibility and localization study of silica-coated CdS QDs in medaka fish embryos, following direct nanoparticle exposure for 24 hours, authenticated the nanomaterials' high potential for in vivo imaging, augmented with superior biocompatibility. As expected, CdS QD-treated embryos showed 100% mortality, whereas the silica-coated QD-treated embryos stayed viable and healthy throughout and after the experiments, devoid of any deformities. We provide highly cogent and convincing evidence for such silica-coated QDs as a model nanoparticle in practice, to achieve in vitro and in vivo precision targeted imaging.
Tuning luminescence of 3d transition- metal doped quantum particles: Ni+2: CdS and Fe+3: CdS
Taheri, S. M.;Yousefi, M. H.;Khosravi, A. A.;
Brazilian Journal of Physics , 2010, DOI: 10.1590/S0103-97332010000300007
Abstract: the room- temperature photoluminescence of cd1- xmxs (m=ni, fe) nanoparticles were investigated. compared with the photoluminescence of cds which peaks at 475 nm, the photoemission of cds:fe nanoparticles was peaking at 537 nm because of fe acting as luminescent centers. on the other hand, the green emission (503 nm) of cds:ni attributed to the 1t2g(d)→ 3a2g(f) raditive transition. with the increase of the ni+2 concentration, photoluminescence intensity is increased while by fe replacement with cd ions, pl intensity is decreased. relative to bulk crystals, due to the quantum confinement effect the band gap of cds clusters is significantly blue- shifted with decreasing cluster size. cds nanoclusters present a mixed hexagonal/cubic structure and with increasing doping concentration the peaks position of doped cds shifts to higher angle.
Time and Temperature Dependence of CdS Nanoparticles Grown in a Polystyrene Matrix
F. Antolini,E. Burresi,L. Stroea,V. Morandi,L. Ortolani,G. Accorsi,M. Blosi
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/815696
Abstract: Luminescent CdS nanocrystals embedded in a polystyrene matrix were successfully prepared. The in situ growth of CdS QDs was realized by thermal treatment of Cd bis(thiolate)/polymer foil at different times and temperatures (240°C and 300°C) of annealing, in order to evaluate their influence on the quantum dots growth process. As a general trend, the increasing of time and temperature of annealing induces a rise of the CdS nanocrystals size into the polymeric matrix. The size distribution, morphology, and structure of the CdS nanoparticles were analysed with HRTEM and XRD experiments. UV-Vis and PL data are strongly size-dependent and were used to investigate the particles' growth process, too. The CdS nanoparticles behavior in solution indicated a general trend of QDs to aggregation. This predisposition was clearly displayed by DLS measurements.
Fabrication of CdS/SnS Heterojunction for Photovoltaic Application  [PDF]
Hongnan Li, Shuying Cheng, Jie Zhang, Weihui Huang, Haifang Zhou, Hongjie Jia
World Journal of Condensed Matter Physics (WJCMP) , 2015, DOI: 10.4236/wjcmp.2015.51002
Abstract: SnS/CdS heterojunction is a promising system for photovoltaic application. SnS thin films were thermally evaporated onto CdS/ITO coated glass substrates. The structure of the device was glass/ ITO/CdS/SnS/In/Ag and I-V curves of the fabricated devices were measured under dark and illuminated conditions, respectively. We discussed the relationship of the thickness and annealing temperature of CdS buffer layers with the performance of SnS/CdS heterojunctions. The optimum thickness and annealing temperature of the CdS buffer layers were 50 nm and 350°C, respectively. The best device had a conversion efficiency of 0.0025%.
Field Emission Properties and Fabrication of CdS Nanotube Arrays  [cached]
Qian Xuemin,Liu Huibiao,Guo Yanbing,Zhu Shiqun
Nanoscale Research Letters , 2009,
Abstract: A large area arrays (ca. 40 cm2) of CdS nanotube on silicon wafer are successfully fabricated by the method of layer-by-layer deposition cycle. The wall thicknesses of CdS nanotubes are tuned by controlling the times of layer-by-layer deposition cycle. The field emission (FE) properties of CdS nanotube arrays are investigated for the first time. The arrays of CdS nanotube with thin wall exhibit better FE properties, a lower turn-on field, and a higher field enhancement factor than that of the arrays of CdS nanotube with thick wall, for which the ratio of length to the wall thickness of the CdS nanotubes have played an important role. With increasing the wall thickness of CdS nanotube, the enhancement factorβdecreases and the values of turn-on field and threshold field increase.
A novel method for tizanidine hydrochloride determination in aqueous solution based on fluorescence quenching of functionalised CdS quantum dots as luminescent probes  [cached]
Marwa Ahmed Fouad,Ehab Farouk Elkady
European Journal of Chemistry , 2012, DOI: 10.5155/eurjchem.3.1.40-43.485
Abstract: A novel, sensitive and convenient method for the determination of tizanidine hydrochloride (TZD) based on the fluorescence quenching of thioglycolic acid-capped CdS quantum dots (TGA-CdS QDs) is proposed. Luminescent CdS semiconductor quantum dots modified by thioglycolic acid were synthesized from cadmium nitrate and sodium sulfide in alkaline aqueous solution. The modified CdS QDs are water-soluble, stable and highly luminescent. When TZD was added into the CdS QDs colloidal solution, the surface of CdS QDs generates the electrostatic interaction in aqueous medium, which induces the quenching of fluorescence emission at 518 nm upon excitation at 340 nm. Under the optimal conditions, the Stern-Volmer calibration plot of F-ο/F against concentration of TZD was linear in the range of 3.0-18.0 μg/mL with a correlation coefficient of 0.9953. The detection limit was 1.35 μg/mL. The relative standard deviation for five determinations of 9 μg/mL TZD was 2.29%. The proposed method was successfully applied to commercial tablets with satisfactory results. The results were found to be in good agreement with those obtained by the reference method. The possible fluorescence quenching mechanism for the reaction is also discussed.
Fabrication Methods and Luminescent Properties of ZnO Materials for Light-Emitting Diodes  [PDF]
Ching-Ting Lee
Materials , 2010, DOI: 10.3390/ma3042218
Abstract: Zinc oxide (ZnO) is a potential candidate material for optoelectronic applications, especially for blue to ultraviolet light emitting devices, due to its fundamental advantages, such as direct wide band gap of 3.37 eV, large exciton binding energy of 60 meV, and high optical gain of 320 cm ?1 at room temperature. Its luminescent properties have been intensively investigated for samples, in the form of bulk, thin film, or nanostructure, prepared by various methods and doped with different impurities. In this paper, we first review briefly the recent progress in this field. Then a comprehensive summary of the research carried out in our laboratory on ZnO preparation and its luminescent properties, will be presented, in which the involved samples include ZnO films and nanorods prepared with different methods and doped with n-type or p-type impurities. The results of ZnO based LEDs will also be discussed.
Simple Non-aqueous Fabrication Route for Oleic Acid Capped Luminescent Cadmium Sulphide Quantum Dots at Relatively Low Temperature  [PDF]
Jayesh Patel, Frej Mighri, Abdellah Ajji
Soft Nanoscience Letters (SNL) , 2011, DOI: 10.4236/snl.2011.13011
Abstract: In this communication, we report a simplistic non-aqueous fabrication route for oleic-acid capped luminescent cadmium sulphide quantum dots at low temperature. The resulting quantum dots, obtained without using any complicated reagents, are cubic in phase, monodispersed and have excellent optical properties. The simplicity of this fabrication route is also promising to develop other oleic acid-capped metal sulphide quantum dots at relatively low temperature.
Fabrication of Thin, Luminescent, Single-crystal Diamond Membranes  [PDF]
Andrew P. Magyar,Jonathan C. Lee,Andi M. Limarga,Igor Aharonovich,Fabian Rol,David R. Clarke,Mengbing Huang,Evelyn L. Hu
Physics , 2011, DOI: 10.1063/1.3628463
Abstract: The formation of single-crystal diamond membranes is an important prerequisite for the fabrication of high-quality optical cavities in this material. Diamond membranes fabricated using lift-off processes involving the creation of a damaged layer through ion implantation often suffer from residual ion damage, which severely limits their usefulness for photonic structures. The current work demonstrates that strategic etch removal of the most highly defective material yields thin, single-crystal diamond membranes with strong photoluminescence and a Raman signature approaching that of single-crystal bulk diamond. These optically-active membranes can form the starting point for fabrication of high-quality optical resonators.
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