Tesis sobre el tema "Zinc Oxide Nanocrystal"
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Newton, Marcus Christian. "Zinc oxide tetrapod nanocrystal diodes". Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1446460/.
Texto completoMuley, Amol. "Synthesis and characterization of nanostructured metallic zinc and zinc oxide". Thesis, Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39101538.
Texto completoSpina, Carla. "Zinc oxide semiconducting nanocrystals : scaffolds for intrinsic and extrinsic defects". Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115869.
Texto completoLander, Sanna. "Rapid microwave assisted growth of ZnO nanocrystals: effects of heating power and zinc precursor". Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-33269.
Texto completoTu, Wei-Lun Scharf Thomas W. "Processing, structure, and tribological property interrelationships in sputtered nanocrystalline ZnO coatings". [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/ark:/67531/metadc12207.
Texto completoZakhtser, Alter. "Synthesis and Reactivity of PtZn Nanostructures and Nanocrystals for Heterogeneous Catalysis Applications". Thesis, Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=http://theses-intra.upmc.fr/modules/resources/download/theses/2019SORUS434.pdf.
Texto completoThe purpose of this thesis was to explore the surface chemistry of platinum-zinc bimetallic systems, and their catalytic activity in the oxidation reaction of CO. The research on this bimetallic system was carried out on two fronts: a surface science study of the model system, a discontinuous ZnO single layer epitaxied on Pt(111), using scanning tunneling microscopy and synchrotron radiation near ambien pressure x-ray photoemission, and a more “nanomaterial science” oriented study of the same bi-metallic system, using complex colloidal synthesis chemistry, transmission and scanning electron microscopy, and finally laboratory XPS. First, a model surface consisting of a ZnO monolayer film supported on Pt(111) was fabricated under ultra-high vacuum conditions. Its surface chemistry was explored by STM and then by synchrotron radiation NAP-XPS under operando conditions. We were able to prove that this system was indeed a typical case of inverse catalysis. Synergetic effects due to the presence of both materials were well seen, but only at low temperatures (up to 410 K). Beyond that temperature, mass transport effects prevent the reactivity of the ZnO/Pt(111) and Pt(111) surfaces from being compared. We have shown that reaction intermediates must be formed in the border area between ZnO and platinum, when the ZnO film is discontinuous. We have highlighted the key role played by the hydroxyls present only ion the ZnO patches, which are due to the dissociation of H2 or H2O from the residual atmosphere on the platinum patches. In particular, we have detected by NAP-XPS the presence of a carboxyl species (due to the association of OH with CO), which precedes the desorption of CO2. Above 410 K, a formate appears, and the latter species is likely a spectator in the CO oxidation process. The transfer of the knowledge accumulated in the preceding surface science and model catalysts studies, to the more realistic case of nanocrystals of the PtZn alloy, while it helped identify some common phenomena, it also shows its limitations. In fact the NC coated with their oleylamine ligands have characteristics that UHV model surfaces do not possess, due to the NC fabrication process itself: we have found spectroscopic hints of the presence of water (possibly a byproduct of the reaction, arising from a condensation reaction between the ketone and the amine); in addition, a capping of the platinum surface by H atoms, is, at present, explanatory of many observed phenomena. Finding the experimental conditions to produce bimetallic nano-alloys from two metal-acac2 precursors was a daunting task, much more than that of physically depositing a thin film on a UHV monocrystal. Our efforts were rewarded as we were able to produce PtZn alloy NCs. This one of the main points of the present study. The presence of Pt(acac)2 prevents zinc (whose from being fully oxidized to ZnO, which is the case when Zn(acac)2 alone is present in oleylamine. Monochromatized XPS shows that zinc makes an alloy with platinum, where it remains metallic, while another fraction is under the form of ZnO. It is not completely clear whether two reaction channels are in competion (PtZn alloying versus Zn oxidation by water), or Zn is oxidized afterwards, i.e. after exposure to air. The alloyed NCs have been studied in detail by advanced methods of electron microscopy (including under operando conditions), diffraction and EDS. Unlike the case of the surface model where the STM images were particularly telling, we do not have at this stage of the study an exact model of the interface between the metal alloy and the zinc oxide that surrounds it. On the other hand, we know that the core of the NCs is occupied by the PtZn alloy, and that the outer planes are identical to those of pure platinum. [...]
Chang, Jin. "Controlled synthesis of inorganic semiconductor nanocrystals and their applications". Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/63960/1/Jin_Chang_Thesis.pdf.
Texto completoUrgessa, Zelalem Nigussa. "Growth and characterization of ZnO nanorods using chemical bath deposition". Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1021124.
Texto completoVahidi, Ghazal. "Application of Cellulose Nanocrystals and Zinc Oxide as a Green Fire-Retardant System in High Density Polyethylene". Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/31725.
Texto completoSeregin, Vladimir Victor. "Part I, Fabrication and surface modification of composite biomaterials based on silicon and calcium disilicide Part II, Synthesis and characterization of erbium doped silicon nanocrystals encapsulated by aluminum and zinc oxides /". Fort Worth, Tex. : Texas Christian University, 2006. http://etd.tcu.edu/etdfiles/available/etd-04252006-145309/unrestricted/seregin.pdf.
Texto completoTu, Wei-Lun. "Processing, Structure, and Tribological Property Interrelationships in Sputtered Nanocrystalline ZnO Coatings". Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc12207/.
Texto completoSantos, Yane Honorato. "Síntese e caracterização de nanocristais de ZnO suportados e não suportados em diatomita e aplicação fotocatalítica". Universidade Federal de Sergipe, 2017. https://ri.ufs.br/handle/riufs/6076.
Texto completoCurrently there are many studies involving Nanocrystals (NC) incorporated into different types of matrices, including, matrices with porous surface. However, little information is known about the incorporation of NC in Diatomite matrix, and there is a lack of studies on the use of this material. In this context, zinc oxide (ZnO) semiconductor nanoparticles were prepared using two sol-gel methods, microwave and autoclave, at 100 ºC and 180 ºC, respectively. The nanocrystals of ZnO obtained by microwaves were incorporated into a matrix of diatomite (DE) in natura and modified. The modifiers used were APTES (3- aminopropyltriethoxysilane) and MPTS (3-Mercaptopropyltrimetoxysilane) for the study. The material DE/ ZnO, in which ZnO was synthesized with mercaptoethanol (ZnO: ME), was applied for the degradation of Methylene Blue (AM) dye, while ZnO, synthesized with diethyleneglycol (ZnO: DEG), was used for degradation of Rhodamine 6G dye (R6G) by photocatalysis. The results of UV-vis and FTIR spectra show that synthesis carried out by heating under adsorption method is more efficient for the incorporation of ZnO in Diatomite matrix. The FTIR spectra showed that the use of modifiers had no significant influence on the structure. According to the UV-Vis spectra, the DE / ZnO material was successful for application to AM photocatalysis and follows a pseudo-first order kinetics. The ZnO:DEG material used for degradation of R6G obtained higher efficiency due to the wide absorption in the UV-Vis of the photocatalyst material.
Atualmente existem diversos estudos envolvendo Nanocristais (NC) incorporados em matrizes de diferentes tipos, incluindo matrizes com uma superfície porosa. Entretanto, pouco se conhece sobre a incorporação de NC em matriz de Diatomita, além de ser limitado a presença de estudos sobre aplicação desse material. Neste contexto, foram preparadas nanopartículas semicondutoras de óxido de Zinco (ZnO) utilizando dois métodos sol-gel, por micro-ondas e autoclave, numa temperatura de 100 ºC e 180 ºC, respectivamente. Os nanocristais de ZnO obtidos por micro-ondas foram incorporados em matriz de Diatomita (DE) in natura e modificada. Foram utilizados os modificadores APTES (3-Aminopropiltrietoxissilano) e MPTS (3- Mercaptopropiltrimetoxissilano) para o estudo. O material de DE/ZnO, no qual o ZnO foi sintetizado com mercaptoetanol (ZnO:ME), foi aplicado para a degradação do corante Azul de Metileno (AM), enquanto o ZnO, sintetizado com dietilenoglicol (ZnO:DEG), não incorporado foi utilizado para degradação do corante Rodamina 6G (R6G) por fotocatálise. Os resultados de UV-Vis e FTIR mostram que a síntese realizada pelo método de adsorção sob aquecimento é mais eficiente para a incorporação de ZnO na matriz de Diatomita. Os espectros de FTIR mostraram que a utilização de modificadores não exerceu influência significativa na estrutura da DE. Segundo os espectros de UV-Vis, o material de DE/ZnO foi bem-sucedido para aplicação em fotocatálise de AM e segue uma cinética de pseudo-primeira ordem. O material de ZnO:DEG utilizado para degradação de R6G obteve maior eficiência devido a ampla absorção no UV-Vis do material fotocatalisador.
Rhodes, Rhys William. "Controlling the morphology of nanoparticle-polymer composite films for potential use in solar cells". Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/controlling-the-morphology-of-nanoparticlepolymer-composite-films-for-potential-use-in-solar-cells(6bc2a3cc-7c11-4615-a202-bead6360af99).html.
Texto completoYou, Chris y 游世豪. "Synthesis of Zinc Oxide Nanocrystal in Microemulsion". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/nk8jwy.
Texto completo國立臺北科技大學
材料及資源工程系所
94
The purpose of this experiment is to synthesize 1-D zinc oxide nanorods using micro-emulsion and calcination. The precursor of nano-sized zinc precipitate was first synthesized using micro-emulsion process. Nano-sized zinc oxide with equi-axial particle form could be synthesized using calcinations, but 1-D zinc oxide was failed to obtain. For producing 1-D zinc oxide nanorods, zinc precipitate mixed with active carbon was calcined, and 1-D zinc oxide was formed at the temperature of above 500℃. The vapor-solid mechanism can be used to interpret the nucleation and crystal growth.
Chitara, Basant. "Properties And Applications Of Semiconductor And Layered Nanomaterials". Thesis, 2012. http://hdl.handle.net/2005/2288.
Texto completo"Synthesis and characterization of transition-metal-doped zinc oxide nanocrystals for spintronics". Thesis, 2007. http://library.cuhk.edu.hk/record=b6074400.
Texto completoFollowing the similar synthetic route, copper- and manganese-doped ZnO nanocrystals have been synthesized and characterized. They both show high-temperature ferromagnetism in line with the aforementioned theoretical model(s). Moreover, they display interesting exchange biasing phenomena at low temperatures, revealing the complexity of magnetic phases therein.
Spintronics (spin transport electr onics), in which both spin and charge of carriers are utilized for information processing, is believed to challenge the current microelectronics and to become the next-generation electronics. Nanostructured spintronic materials and their synthetic methodologies are of paramount importance for manufacturing future nanoscale spintronic devices. This thesis aims at studying synthesis, characterization, and magnetism of transition-metal-doped zinc oxide (ZnO) nanocrystals---a diluted magnetic semiconductor (DMS)---for potential applications in future nano-spintronics.
The crystal growth strategy demonstrated in this work not only provides a more convenient approach to directly tailor magnetic properties of advanced multifunctional spintronic materials on a nanometer scale but also contributes to a deeper insight into the microscopic origin of magnetism in wide-band-gap oxide DMSs.
Wang, Xuefeng.
"August 2007."
Adviser: J. B. Xu.
Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1230.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2007.
Includes bibliographical references.
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract in English and Chinese.
School code: 1307.
JHAN, JHONG-CI y 詹忠奇. "Synthesis and Optical Characterization of Zinc Oxide Nanocrystals". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/57450809176887924877.
Texto completoCai, Jia-Ming y 蔡佳銘. "Surface modification and dispersion of Zinc oxide nanocrystals". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/06035432152696005879.
Texto completo國立中央大學
化學工程與材料工程研究所
94
Abstract A highly effective and large scale method was found to transfer ZnO nanocrystals (~5.7nm NCs) prepared in EG to non-polar solvents. This was accomplished by capping the ZnO NCs with Oleic acid (OA) or Linoleic acid (LinOA). FTIR and TGA analysis indicated that OA is bonded to surface of ZnO by bidentate chelating and controlled chelating types could be possible.The amount of capping agent required was ~8 molecule/nm2. The capped NCs formed a highly transparent (T>90%) dispersion in n-hexane even at 16wt%. The dispersed NCs could be further coated with silica or alkyl silane in the non-polar solvent via the nano-emulsion method then transfer back to polar solvent. The so obtained ZnO@SiO2 nanoparticles showed a very high Photoluminescence efficiency in aqueous suspension. The ZnO@SiO2 nanoparticles obtained exhibited a broad green emission band at about 535nm in aqueous suspension and yellow-orange emission band at 590nm as bulk pieces. The further application were disirable for functional nanocomposites and optical material.
Rakshit, Sabyasachi. "Resonance Energy Transfer Using ZnO Nanocrystals And Magnetism In The Mixed Metal Layered Thiophosphates, Mn1-xFexPS3(0≤x≥1)". Thesis, 2009. http://etd.iisc.ernet.in/handle/2005/2156.
Texto completoAka, Tiemele Wilfried Anderson. "Investigation of the effects of zinc oxide nanoparticles and synthesized cellulose nanocrystals (CNCs) on emulsion-based drilling fluids". Thesis, 2019. https://hdl.handle.net/10539/30622.
Texto completoDrilling Mud holds an important role in the drilling process in such a way that it is a determinant key to the success of the operation as well as the money spent throughout the process. Indeed the success and the cost of the operation can be severely impacted by some challenges experienced while drilling such as temperature and pressure conditions which leads to fluid loss, fluid deterioration...As a result there is a need to formulate a fluid with desirable rheological properties to withstand such undesirable parameters. Therefore this work was aimed to improve emulsion drilling fluids (EDFs) based nanoparticles with enhanced properties. Many investigations were performed to find a proper emulsion stability as well as a good drilling fluid performance. The stability of the prepared emulsion drilling fluids was done using surfactant with different concentrations for several days. After several days of preparation, the EDFs containing DTAB as surfactant have showed a better emulsion stabilizer compared to the Triton X-100 ones. In addition an investigation combining both NPs and surfactants confirmed the used of NPs to improve DF and revealed the effective use of ZnO NPs for drilling fluids application and preferentially with DTAB as surfactant. Following that result, the 2nd part of the work was based on the synthesis and characterization of CNCs as NPs to formulate EDF with DTAB as surfactant. The CNCs NPS were successfully obtained via the method of oxidation of microfibrillated cellulose through TEMPO-mediate and after characterization using TEM, spherical NPs with small size varying from 10-50nm were observed. The FANN® Model 35 viscometer served to display the behavior of the shear stress and viscosity of the prepared fluids against variable shear rate at variable NPs and temperature concentration. The rheological and filtration properties were increase with increase in CNCs content from 0.8 to 1.2% of fluid in room temperature and with an increase in temperature.
PH2021
Singh, Tejinder. "Atomic-scale Modeling of Transition-metal Doping of Semiconductor Nanocrystals". 2011. https://scholarworks.umass.edu/open_access_dissertations/356.
Texto completoChoi, Chang-Ho. "Synthesis of colloidal metal oxide nanocrystals and nanostructured surfaces using a continuous flow microreactor system and their applications in two-phase boiling heat transfer". Thesis, 2013. http://hdl.handle.net/1957/37900.
Texto completoGraduation date: 2013
Sai, Ranajit. "Development of CMOS-Compatible, Microwave-Assisted Solution Processing of Nanostructured Zine Ferrite Films for Gigahertz Circuits". Thesis, 2013. http://etd.iisc.ernet.in/2005/3412.
Texto completo"PART I: FABRICATION AND SURFACE MODIFICATION OF COMPOSITE BIOMATERIALS BASED ON SILICON AND CALCIUM DISILICIDE; PART II: SYNTHESIS AND CHARACTERIZATION OF ERBIUM DOPED SILICON NANOCRYSTALS ENCAPSULATED BY ALUMINUM AND ZINC OXIDES". Texas Christian University, 2006. http://etd.tcu.edu/etdfiles/available/etd-04252006-145309/.
Texto completoLal, Nidhi. "Interfacing Biomolecules with Nanomaterials for Novel Applications". Thesis, 2014. http://hdl.handle.net/2005/3222.
Texto completo