Academic literature on the topic 'Metal doping'

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Journal articles on the topic "Metal doping"

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Wang, Ting, Yan Dong Mao, Fang Peng Tang, Jun Xing, and Li Guang Wu. "Crystallization and Photocatalytic-Activity of TiO2 Doped with Metal Ions Prepared by Adsorption Phase Synthesis." Advanced Materials Research 624 (December 2012): 194–99. http://dx.doi.org/10.4028/www.scientific.net/amr.624.194.

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TiO2 photocatalysts doped with different metal ions were prepared by adsorption phase synthesis. The influence of different dopant metal ions with various concentrations on the crystallization of TiO2 was ex-plored by XRD. Then photodegradation experiments of methyl-orange were employed to evaluate the activity of these photocatalysts. The results indicated that the crystallization of TiO2 was restricted after doping, due to replacement of Ti4+ in TiO2 lattice structure by other metal ions. And the restriction became stronger with radius and concentration of doping ions increasing. There was an optimum dopant concentration appeared during preparation of TiO2 doped with Cd2+ and Fe3+. When dopant concentration was less or more than this optimum value, the photocatalytic activity of TiO2 doped with metal ions was lower than that of TiO2 without doping. Since radius of Fe3+ was close to Ti4+, the influence of Fe3+ dopant concentration on crystallization and activity of TiO2 was more obvious than that of Cd2+ doping.
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Hua, L., and L. Zhang. "Effect of In, Bi, Zn Binary-Metal Dopings in Sn-0.7Cu Solder on its Electrochemical Corrosion Charateristics in 3 wt.% NaCl Solution." Advanced Materials Research 548 (July 2012): 286–92. http://dx.doi.org/10.4028/www.scientific.net/amr.548.286.

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Effect of In, Zn, Bi binary-metal dopings in Sn-0.7Cu (SC) solder on the electrochemical corrosion characteristics of SC solder were conducted, the potentiodynamic polarization test coupled with SEM analyses had been widely used to study the corrosion properties of alloy materials. The results showed that when both In-Zn binary-metal doping was increased, the corrosive current density (Icorr) increased, which proved that anti-corrosion capacities of Sn-0.7Cu solder decreased with In-Zn doping increasing, the affected order was Zn>In. When both In-Bi binary-metal doping percent were increased, the corrosive current density (Icorr) decreased, the affected order was In>Bi. When both Zn-Bi binary-metal doping percent were increased, the Icorr increased, the affected order was Zn>Bi. There was collaborated function on SC solder for the three metals. The synthesized result showed that the sequence of In, Bi, Zn affecting on corrosion of SC solder was that Zn>In>Bi, which provide a support data to improve soldering reliability in electronic packagings.
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Rojanasuwan, Sunit, Pakorn Prajuabwan, Annop Chanhom, Anuchit Jaruvanawat, Adirek Rangkasikorn, and Jiti Nukeaw. "The Effect of the Central Metal Atom on the Structural Phase Transition of Indium Doped Metal Phthalocyanine." Advanced Materials Research 717 (July 2013): 146–52. http://dx.doi.org/10.4028/www.scientific.net/amr.717.146.

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We investigate the effect of central metal atom on the phthalocyanine (Pc) molecular crystals as intercalated with indium. As dopant, indium has physical interaction with some atom in the ring of Pc molecule and there is charge transfer between indium atom and Pc ring atom. Since In-doped Pc is a hole doping which increase positive charge carriers and the HOMO of ZnPc, CuPc, NiPc and MgPc are localized on the phthalocyanine ring, then, the central metal atom e.g. Zn, Cu, Ni and Mg are not directly involved with the charge transfer between indium dopant and their Pc molecule. The structural phase transition from α phase to β phase of ZnPc upon doping with indium is another evidence for the existing of charge transfer between dopant atom and matrix Pc molecule. A comparative experiment of optical absorption spectrum of each metal Pc reveals that the central metal atom will affect the forming of crystal structure whether will be α phase or β phase as intercalated with indium.
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Zhang, Siyuan, Hsun Jen Chuang, Son T. Le, Curt A. Richter, Kathleen M. McCreary, Berend T. Jonker, Angela R. Hight Walker, and Christina A. Hacker. "Control of the Schottky barrier height in monolayer WS2 FETs using molecular doping." AIP Advances 12, no. 8 (August 1, 2022): 085222. http://dx.doi.org/10.1063/5.0101033.

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Developing controllable doping processes for two-dimensional (2D) semiconductors is critical to developing next-generation electronic and optoelectronic devices. Understanding the nature of the contacts is an essential step in realizing efficient charge injection in transition metal dichalcogenides. In this study, post-growth n-doping of chemical vapor deposition grown monolayer (1 L) WS2 is achieved through molecular reductant solution treatment. The doping level can be effectively controlled by the treatment time and dopant solution concentrations. The doped WS2 field-effect transistors showed profound threshold voltage shifts and tunable channel currents. This molecular n-doping technique is beneficial for the selective area doping needed for electrical contacts and reduces the contact resistance ( Rc) in 1 L WS2 by more than two orders of magnitude. The significant reduction of Rc is attributed to the high electron-doping density achieved in WS2, which leads to a significant reduction of the Schottky barrier height. The dependence of mobility on temperature indicates clear evidence of the strong suppression of charge-impurity scattering after doping. High levels of doping allow the observation of a metal–insulator transition in monolayer WS2 due to strong electron–electron interactions. This doping technique provides a viable route for tailoring the electrical properties and improving the contacts in transition metal dichalcogenides, paving the way for high-performance 2D nanoelectronic devices.
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Carey, J. J., and M. Nolan. "Cation doping size effect for methane activation on alkaline earth metal doping of the CeO2 (111) surface." Catalysis Science & Technology 6, no. 10 (2016): 3544–58. http://dx.doi.org/10.1039/c5cy01787d.

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Mogal, Sajid I., Manish Mishra, Vimal G. Gandhi, and Rajesh J. Tayade. "Metal Doped Titanium Dioxide: Synthesis and Effect of Metal Ions on Physico-Chemical and Photocatalytic Properties." Materials Science Forum 734 (December 2012): 364–78. http://dx.doi.org/10.4028/www.scientific.net/msf.734.364.

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Titanium dioxide (Titania; TiO2) is one of the most widely used metal oxide semiconductor in the field of photocatalysis for removal of pollutants. It has been noted that titanium dioxide is a research friendly material as its physico-chemical and catalytic properties can be easily altered as per specific application. Since many years, researchers have tried to modify the properties of titanium dioxide by means of doping with metals and non-metals to improve its performance for photocatalytic degradation (PCD) applications. The doping of various metal ions like Ag, Ni, Co, Au, Cu, V, Ru, Fe, La, Pt, Cr, Ce, etc. in titanium dioxide have been found to be influencing the band gap, surface area, particle size, thermal property, etc. and therefore the photocatalytic activity in PCD. Moreover, photocatalytic activity of doped titanium dioxide has been observed in visible light range (i.e., at wavelength >400 nm). In this review, different synthesis route for doping of metal ions in titanium dioxide have been emphasised. The effect of metal dopant on the structural, textural and photocatalytic properties of titanium dioxide has been reviewed.
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Periyat, Pradeepan, Binu Naufal, and Sanjay Gopal Ullattil. "A Review on High Temperature Stable Anatase TiO2 Photocatalysts." Materials Science Forum 855 (May 2016): 78–93. http://dx.doi.org/10.4028/www.scientific.net/msf.855.78.

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This review focuses on the recent developments of high temperature stable anatase TiO2 photocatalyst. Eventhough TiO2 exists in different forms anatase, rutile and brookite, anatase phase stabilization is often the key to obtain the highest photocatalytic performance for TiO2, particularly for the use as an antibacterial and self-cleaning coatings in high temperature processed ceramics. Different methods available for the anatase stabilization in literature are critically reviewed and emphasis is placed on relatively recent developments. Currently available methods of anatase stabilizations are classified in to four categories viz (i) doping with metal ions (ii) doping with non-metal ions (iii) co-doping with metal and non-metal ions and (iv) dopant free stabilization by oxygen richness. Further to this, the application of these high temperature stabilized anatase TiO2 photocatalyst on various ceramics substrates such as tile, glass and sanitary wares as self-cleaning and antibacterial coatings are also been briefly discussed.
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Li, Bin, Yihan Zhang, Yang Liu, Yiwen Ren, Xiaoting Zhu, Lingjie Sun, Xiaotao Zhang, Fangxu Yang, Rongjin Li, and Wenping Hu. "Highly Efficient Contact Doping for High-Performance Organic UV-Sensitive Phototransistors." Crystals 12, no. 5 (May 2, 2022): 651. http://dx.doi.org/10.3390/cryst12050651.

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Organic ultraviolet (UV) phototransistors are promising for diverse applications. However, wide-bandgap organic semiconductors (OSCs) with intense UV absorption tend to exhibit large contact resistance (Rc) because of an energy-level mismatch with metal electrodes. Herein, we discovered that the molecular dopant of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) was more efficient than the transition metal oxide dopant of MoO3 in doping a wide-bandgap OSC, although the former showed smaller electron affinity (EA). By efficient contact doping, a low Rc of 889 Ω·cm and a high mobility of 13.89 cm2V−1s−1 were achieved. As a result, UV-sensitive phototransistors showed high photosensitivity and responsivity.
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Dzhumanov, S. "METAL-INSULATOR TRANSITIONS IN DOPED La-BASED SUPER CONDUCTORS WITH SMALL-RADIUS DOPANTS." Eurasian Physical Technical Journal 19, no. 1 (39) (March 28, 2022): 15–19. http://dx.doi.org/10.31489/2022no1/15-19.

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n this work, we study the possibility of realizing two distinct mechanisms of metal-insulator transitions in hole-doped cuprates induced by the localization of charge carriers near the small-radius impurities and in a deformable lattice (i.e. in the absence of impurities). The purpose of this research is to determine the criteria (i.e. conditions) for the existence of the localized states of hole carriers and solve the problem of metal-insulator transitions in La-based cuprates. The advantage of La-based cuprate versus other types of cuprates is that two distinct metal-insulator transitions in La-based cuprates driven by the strong carrier-impurity-phonon and carrier-phonon interactions occur simultaneously in a wider doping range from the lightly doped to heavily doping regime. We show that at very low doping, the separate levels of hole carriers localized near impurities and in a deformable lattice are formed in the charge-transfer gap of the cuprates. As the doping level increases towards underdoped region, the energy levels of such charge carriers start to form energy bands which gradually broaden with increasing doping. We propose a new two-carrier cuprate superconductor model for studying two distinct metal-insulator transitions occurring simultaneouslyin hole-doped La-based cuprate compounds. We demonstrate that when hole carriers reside in impurity and polaron bands, these metal-insulator transitions in La-based superconductors with small-radius dopants occur accordingly in a wide doping range and relatively lower doping levels.
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Han, Juan, Xu Wu, Julia Xiaojun Zhao, and David T. Pierce. "An Unprecedented Metal Distribution in Silica Nanoparticles Determined by Single-Particle Inductively Coupled Plasma Mass Spectrometry." Nanomaterials 14, no. 7 (April 6, 2024): 637. http://dx.doi.org/10.3390/nano14070637.

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Metal-containing nanoparticles are now common in applications ranging from catalysts to biomarkers. However, little research has focused on per-particle metal content in multicomponent nanoparticles. In this work, we used single-particle inductively coupled plasma mass spectrometry (ICP-MS) to determine the per-particle metal content of silica nanoparticles doped with tris(2,2′-bipyridyl)ruthenium(II). Monodispersed silica nanoparticles with varied Ru doping levels were prepared using a water-in-oil microemulsion method. These nanoparticles were characterized using common bulk-sample methods such as absorbance spectroscopy and conventional ICP-MS, and also with single-particle ICP-MS. The results showed that averaged concentrations of metal dopant measured per-particle by single-particle ICP-MS were consistent with the bulk-sample methods over a wide range of dopant levels. However, the per-particle amount of metal varied greatly and did not adhere to the usual Gaussian distribution encountered with one-component nanoparticles, such as gold or silver. Instead, the amount of metal dopant per silica particle showed an unexpected geometric distribution regardless of the prepared doping levels. The results indicate that an unusual metal dispersal mechanism is taking place during the microemulsion synthesis, and they challenge a common assumption that doped silica nanoparticles have the same metal content as the average measured by bulk-sample methods.
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Dissertations / Theses on the topic "Metal doping"

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Crawford, Kevin G. "Surface transfer doping of diamond using transition metal oxides." Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8561/.

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This thesis presents a body of work which advances the use of single crystal hydrogen terminated diamond as a semiconducting material. Surface transfer doping of intrinsic diamond is investigated, examining the current state of this technology and its limitations. New techniques for producing robust, thermally stable surface transfer doped diamond were achieved through use of transition metal oxides such as MoO3 and V2O5, as demonstrated experimentally by way of Hall measurement. Through use of these materials, thermal stability was greatly increased up to temperatures of at least 300oC. To achieve this higher temperature operation, encapsulation of MoO3 and V2O5 was found to be necessary in maintaining conductivity of the diamond surface due to suspected thermally-induced loss of hydrogen termination. Similarly, long term atmospheric stability is shown to necessitate annealing of the diamond surface prior to oxide deposition and for thinner layers of oxide, down to 10 nm, encapsulation of the oxide to isolate from atmosphere is shown to be required for increased stability. As well as the improvements in stability offered by these transition metal oxides, sheet resistance of the hydrogen terminated diamond surface was also greatly reduced. Carrier densities as high as ~7.5 ×1013 cm-2 were observed for MoO3-induced surface transfer doping, resulting in a low sheet resistance of ~ 3 kΩ/□. In parallel to the development of oxide acceptor materials, conditioning of the diamond surface was explored using Atomic Force Microscopy (AFM). Techniques for smoothing the surface after mechanical polishing were developed by way of RIE and ICP etching using both chlorine and oxygen mixtures. Surface roughness down to 2 angstroms was demonstrated, showing a significant improvement in roughness over mechanical polishing alone. Similarly, observed defects produced by polishing induced damage were removed through use of this etching strategy. The effects of varied plasma density during hydrogen termination was explored on etched surfaces, which produced higher quality hydrogen-terminated surfaces as verified by surface conductivity and AFM measurements. Finally, incorporation of MoO3 into a preliminary Field Effect Transistor (FET) device on diamond was attempted. Fabrication techniques to produce a FET device on hydrogen-terminated diamond is shown with preliminary results of MoO3 encapsulated devices. Insights into the fabrication of ohmic and gate contacts, incorporating MoO3, is also discussed.
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Taub, Samuel. "Transition metal oxide doping of ceria-based solid solutions." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/18845.

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The effects of low concentration Co, Cr and Mn oxide, singly and in combination, on the sintering and electrical properties of Ce0.9Gd0.1O1.95 (CGO) have been investigated with possible mechanisms suggested to explain this modified behaviour. The influence of these dopants on the densification kinetics of CGO were primarily investigated using constant heating rate dilatometry. Whilst low concentration Co and Mn-oxide were found to improve the sinterability of CGO, the addition of Cr-oxide was found to inhibit the densification kinetics of the material. The location and concentration of these dopants were investigated as a function of relative density using scanning transmission electron microscopy combined with energy dispersive x-ray mapping. All materials showed a gradual reduction in the grain boundary dopant concentration with sintering time, leading eventually to the formation of a second phase that was subsequently analysed by either electron energy loss spectroscopy or synchrotron x-ray powder diffraction. The improved densification of both the Co-doped and Mn-doped materials was believed to be related to an increased rate of lattice and grain boundary cation diffusion, associated with the segregation of the transition metal dopant to the grain boundary. In both cases the onset of rapid densification was correlated with the reduction of the transition metal cation leading to an increase in cerium interstitials, which are suggested to be the defects responsible for cerium diffusion. The inhibiting effects of Cr-addition were similarly related to changes in the defect chemistry, with the Cr ions creating a blocking effect that hindered the dominant grain boundary pathway for cation diffusion. The effects of these dopants on the electrical conductivity of CGO were examined using a combination of AC impedance spectroscopy and Hebb-Wagner polarisation measurements. Whilst Co-doping was found to enhance the specific grain boundary conductivity of CGO, the addition of either Cr or Mn resulted in an approximate 2 orders of magnitude decrease, even at dopant concentrations as low as 100 ppm. Despite these differences in ionic conductivity, both Co and Cr-doping were found to significantly enhance the electronic contribution to the conductivity along the boundaries, particularly within the p-type regime. The modified electrical behaviour was related to the formation of a continuous, transition metal-enriched grain boundary pathway and a change in the driving force for grain boundary Gd segregation, leading to a depletion of oxygen vacancies within the space charge regions and the consequent reduction of oxygen transport across the boundaries. The effects of this segregation were finally examined with mono-layer sensitivity using low energy ion scattering incorporating a novel method of self-standardisation. These analyses provided strong support for the conductivity mechanisms previously outlined.
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Fei, Wenwen. "Au25(SR)18: Metal Doping, Ligand Exchange, and Fusion Reactions." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3424837.

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In the past few years, the interest in the study of atomically precise metal nanoclusters has grown very significantly. Main reasons are the refined techniques nowadays available for controlling their structure and composition, their often-intriguing properties, and the possibility to tailor them for specific applications. This Thesis aims at providing new tools to synthesize, control, modify, and characterize thiolate-protected gold nanoclusters. The focus of the research is on the thiolate-protected Au25(SR)18 cluster, which is considered by many the true benchmark system for the study of atomically precise nanoclusters. Due to quantum-confinement effects, these nanoclusters have discrete electron-energy states, and this causes the emergence of molecular properties, such as a HOMO-LUMO gap, distinct optical and redox behavior, and magnetism. Additionally, the composition of the metal part and/or the capping monolayer can be modified to make the cluster exhibit specific, sometimes unexpected properties. The goal of this research is to show that by performing controlled modifications of the cluster core and protecting monolayer, one can indeed introduce new properties, and thereby, explore new frontiers for possible applications of these nanosystems. From the viewpoint of the metal, Au25(SR)18 was modified by introducing one-single foreign metal atom. The synthetic, purification, modification, and characterization procedures were refined to explore new ways for achieving proper understanding of the structure of the doped molecular cluster. Particular emphasis has been put on the NMR characterization of the products, a still unexplored yet very powerful tool to localize the position of the doping metal. It is shown that the actual position of the doping metal changes depending on the element. The effect of Au25 doping is then explored from the viewpoint of the generation and detection of singlet oxygen, which is an area of tremendous interest for the treatment of cancer via photodynamic therapy. Metal nanoclusters exhibit discrete optical transitions and have sufficiently long-lived triplet excited states. This makes them react quite efficiently with triplet ground-state oxygen to form singlet excited-state oxygen. Here we show that by proper tuning of the cluster composition (doping metals and ligands), these nanosystems can be made to exhibit the same singlet-oxygen photosensitization performance of systems currently used in the medical practice. We discovered an intriguing transformation of Au25 core. This can be considered as a fusion reaction that consists in the spontaneous transformation of two Au25(SR)18 clusters to form Au38(SR)24, which is another benchmark gold nanocluster. The radical nature of Au25(SR)180 appears to play an important role in this bimolecular reaction that, importantly, does not require addition of exogenous thiols or other co-reactants. This is indeed a very unexpected result that could modify our view about the relative stability of molecular gold nanoclusters. After exploring core modifications, we also investigated strategies to carry out chemical reactions, namely polymerization, directly on the cluster monolayer. Proper functionalization of the nanocluster, that is, capping the cluster with different thiolates, relies on the possibility of either preparing the cluster directly, starting from a mixture of appropriate thiols, or taking advantage of ligand-place exchange reactions, in which the native thiolates present in preformed clusters are partially exchanged with other thiols. In this Thesis, we have implemented experimental conditions for controlling ligand-place exchange reactions on Au25(SR)18 with the goal of introducing functional groups suitable to react with a specific monomer. After polymerization, a polylysine protected Au25 cluster could be prepared.
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Trapatseli, Maria. "Doping controlled resistive switching dynamics in transition metal oxide thin films." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/423702/.

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Transition metal oxide thin films have attracted increasing attention due to their potential in non-volatile resistive random access memory (RRAM) devices, where such thin films are used as active layers in metal-insulator-metal (MIM) configurations. Titanium dioxide is one of the most celebrated oxides among the ones that exhibit resistive switching behaviour due to its wide band gap, high thermal stability, and high dielectric constant. RRAM devices with various materials as active layers, have demonstrated very fast switching performance but also huge potential for miniaturisation, which is the bottleneck of FLASH memory. Nevertheless, these devices very often suffer poor endurance, physical degradation, large variability of switching parameters and low yields. In most cases, the physical degradation stems from high electroforming and switching voltages. Doping of the active layer has been often employed to enhance the performance of RRAM devices, like endurance, OFF/ON ratio, forming voltages, etc. In this work, doping in TiO2-x RRAM devices was used to engineer the electroforming and switching thresholds so that device degradation and failure can be delayed or prevented. Al and Nb were selected with basic criteria the ionic radius and the oxidation state. The doped RRAM devices, showed improved switching performance compared to their undoped counterparts. Alternative approaches to doping were also investigated, like multilayer stacks comprising Al2O3-y and TiO2-x thin films. Furthermore, Al:TiO2-x/Nb:TiO2-x bilayer RRAM devices were fabricated, to prove whether a diode behaviour of the p-n interface inside the RRAM was feasible. The latest would be a particularly interesting finding towards active electronics.
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PRADA, STEFANO. "Enhancing oxide surface reactivity by doping or nano-structuring." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/50011.

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Wide band-gap simple oxides are rather inert materials, which found applications in heterogeneous catalysis mainly as supports for active metal nanoparticles. This thesis investigates tailored modifications of the oxide characteristics aimed at making these substrates more reactive in catalytic processes. In particular we are interested in engineering the charge transfer with supported metal catalysts in order to enhance their activity and selectivity. By using first principles calculations in the framework of the density functional theory, we have explored two main routes in this field: 1) nanostructuring, in particular nanothick oxide films supported on metals, and 2) doping of oxides with substitutional metal ions. After addressing methodological aspects related to the theoretical simulations of these materials, we have considered the role of oxide doping in optimizing the structural and electronic properties of supported gold adparticles; we have shown that depending on the dopant and the nature of the oxide it is possible to finely tune the shape and the charge state of adsorbed metal particle. Moreover we have combined oxide doping and nanostructuring in modifying the work function of metal substrates. By varying parameters like nature, position, and concentration of dopants within the metal-supported oxide films, it is possible in principle to modify the work function of the metallic support in a desired way.
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Derk, Alan Richard. "Understanding and Controlling Light Alkane Reactivity on Metal Oxides| Optimization Through Doping." Thesis, University of California, Santa Barbara, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3724768.

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Metal oxide catalysts have numerous industrial applications and have garnered research attention. Although oxides catalyze many important reactions, their yields to products are too low to be of economic value due to low conversion and/or low selectivity. For example, some oxides can catalyze the conversion of methane to intermediates or products that are liquefiable at yields no higher than 30%. With improved yield, such a process could help reduce the trillions of cubic feet of natural gas flared every year, saving billions of dollars and millions of tonnes of greenhouse gases. To this end, one goal of this work is to understand and improve the catalytic activity of oxides by substituting a small fraction of the cations of a "host oxide" with a different cation, a "dopant." This substitution disrupts chemical bonding at the surface of the host oxide, which can improve reactant and lattice oxygen activation where the reaction takes place. Another goal of this work is to combine catalysts with metal oxides reactants to improve thermodynamic limitations. Outstanding challenges for the study of doped metal oxide catalysts include (1) selection of dopants to ix synthesize within a host oxide and (2) understanding the nature of the surface of the doped oxide during reaction.

Herein, strongly coupled theoretical calculations and experimental techniques are employed to design, synthesize, characterize, and catalytically analyze doped oxide catalysts for the optimization of light alkane conversion processes. Density Functional Theory calculations are used to predict different energies believed to be involved in the reaction mechanism. These parameters offer valuable suggestions on which dopants may perform with highest yield and activity and why. Synthesis is accomplished using a combination of wet chemical techniques, suited specifically for the preparation of doped (rather than supported or mixed) metal oxide catalysts of high surface area and high reactivity. Characterization is paramount in any doped-oxide investigation to determine if the catalyst under reaction conditions is truly doped or merely small clusters of supported catalyst. With that goal, diffraction, X-ray, electron microscopies, infrared spectroscopy, and chemical probes are used to determine the nanoscopic nature of the catalysts. Additional novel measurement techniques, such as transient oxidation reaction spectroscopy, determined the nature of the active site's oxidation state.

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Crowley, Kyle McKinley. "Electrical Characterization, Transport, and Doping Effects in Two-Dimensional Transition Metal Oxides." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1597327584506971.

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Banerjee, Tanushree. "Impact of Nickel Doping on Hydrogen Storage in Porous Metal-Organic Frameworks." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2265.

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A supply of clean, carbon neutral and sustainable energy is the most scientific and technical challenge that humanity is facing in the 21st century. Though there is enough fossil fuels available for a few centuries, their use would increase the level of CO2 in the atmosphere. This would lead to global warming and may pose serious threats such as rising of sea level, change in hydrological cycle, etc. Hence there is a need for an alternative source of fuel that is clean and sustainable. Among the many resources considered as an alternative power source, hydrogen is considered one of the most promising candidates. To use hydrogen commercially, appropriate hydrogen storage system is required. Various options to store hydrogen for onboard use include gaseous form in high-pressure tanks, liquid form in cryogenic conditions, solid form in chemical or metal hydrides, or by physisorption of hydrogen on porous materials. One of the emerging porous materials are metal-organic frameworks (MOFs) which provide several advantages over zeolites and carbon materials because the MOFs can be designed to possess variable pore size, dimensions, and metrics. In general, MOFs adsorb hydrogen through weak interactions such as London dispersion and electrostatic potential which lead to low binding enthalpies in the range of 4 to 10 kJ/mol. As a result, cryogenic conditions are required to store sufficient amounts of hydrogen inside MOFs. Up to date several MOFs have been designed and tested for hydrogen storage at variable temperature and pressure levels. The overall results thus far suggest that the use of MOFs for hydrogen storage without chemical and electronic modifications such as doping with electropositive metals or incorporating low density elements such as boron in the MOFs backbone will not yield practical storage media. Such modifications are required to meet gravimetric and volumetric constraints. With these considerations in mind, we have selected a Cr-based MOF (MIL-101; Cr(F,OH)-(H2O)2O[(O2C)-C6H4-(CO2)]3•nH2O (n ≈ 25)) to investigate the impact of nickel inclusion inside the pores of MIL-101 on its performance in hydrogen storage. MIL-101 has a very high Langmuir surface area (5900 m2/g) and two types of mesoporous cavities (2.7 and 3.4 nm) and exhibits exceptional chemical and thermal stabilities. Without any modifications, MIL-101 can store hydrogen reversibly with adsorption enthalpy of 10 kJ/mol which is the highest ever reported among MOFs. At 298 K and 86 bar, MIL-101 can store only 0.36 wt% of hydrogen. Further improvement of hydrogen storage to 5.5 wt% at 40 bar was achieved only at low temperatures (77.3 K). As reported in the literature, hydrogen storage could be improved by doping metals such as Pt. Doping is known to improve hydrogen storage by spillover mechanism and Kubas interaction. Hence we proposed that doping MIL-101 with a relatively light metal possessing large electron density could improve hydrogen adsorption. Preferential Ni doping of the MIL-101’s large cavities which usually do not contribute to hydrogen uptake is believed to improve hydrogen uptake by increasing the potential surface in those cavities. We have used incipient wetness impregnation method to dope MIL-101 with Ni nanoparticles (NPs) and investigated their effect on hydrogen uptake at 77.3 K and 298 K, at 1 bar. In addition, the impact of metal doping on the surface area and pore size distribution of the parent MIL-101 was addressed. Metal content and NPs size was investigated by ICP and TEM, respectively. Furthermore, crystallinity of the resulting doped samples was confirmed by Powder X-ray Diffraction (PXRD) technique. The results of our studies on the successful doping with Ni NPs and their impact on hydrogen adsorption are discussed.
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Buta, Sarah H. (Sarah Hume) 1972. "A first principles investigation of transitional metal doping in lithium battery cathode materials." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9550.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1999.
Includes bibliographical references (p. 77-82).
The goal of this work is to understand the properties of mixed-metal intercalation oxides. Using first-principles methods, the effect of doping on the mixing, energetic, and voltage properties as well as the phase diagrams of lithium transition-metal oxides for lithium battery cathode materials was investigated. The effect of doping on the phase separation tendencies of layered transition-metal oxides was examined and it was found that for normal processing temperatures, Al is miscible in layered transition metal oxides (LiMO2) for five of the eight first-row transition metals studied. Temperature-composition phase diagrams for both Li(Al,Co)O2 and Li(Al,Cr)O2 were calculated. In these two systems, Al-doping is limited above 600°C by the formation of [gamma]-LiA1O2 and at very low temperatures owing to the existence of a miscibility gap. Reduced solubility is expected in the layered phase above 600°C for all oxides which have substantial solubility with LiA1O2 due to the formation of yLiAlO2. The effect of transition-metal doping on the average voltage properties in Mn-based spinets was calculated and the large increase in average voltage found experimentally was reproduced. A detailed analysis on the layered structure Li(Al,Co)O2 was performed, studying the energetics of different lithium sites and the effect of short-range clustering on the shape of the voltage curve. Though the average voltage is raised by Al substitution, the unexpected stability of sites with a few Al nearest neighbors leads to an initial decrease in voltage. For the Al-doped LiCoO2 system, a step in the voltage curve is found only for micro-segregated materials. When the Al and Co ions are randomly distributed in a solid solution, the voltage curve shows a continuous, gradual slope. The effect of oxygen defects in the Li(Al,Co)O2 system was investigated. A model for the effect of oxygen vacancies on the free energy of doped layered oxides was created by combining an ideal gas approximation and first-principles energy defect calculations. The results qualitatively confirm experimental studies on oxygen release in lithium battery materials.
by Sarah H. Buta.
S.M.
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Wang, Junwei. "Chemical doping of metal oxide nanomaterials and characterization of their physical-chemical properties." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1333829935.

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Books on the topic "Metal doping"

1

Kaschieva, S. Radiation defects in ion implanted and/or high-energy irradiated MOS structures. Hauppauge, N.Y: Nova Science Publishers, 2009.

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Matty, Caymax, Materials Research Society Meeting, and Symposium on High-Mobility Group-IV Materials and Devices (2004 : Francisco, Calif.), eds. High-mobility group-IV materials and devices: Symposium held April 13-15, 2004, San Francisco, California, U.S.A. Warrendale, Pa: Materials Research Society, 2004.

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International Conference on Heavy Doping and the Metal-Insulator Transition in Semiconductors (1984 Santa Cruz). Heavy doping and the metal-insulator transition in semiconductors: International conference, University of California at Santa Cruz, California, U.S.A., 30 July-3 August 1984. Edited by Landsberg P. T. 1922-. New York: Pergamon Press, 1985.

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Kaschieva, S. Radiation defects in ion implanted and/or high-energy irradiated MOS structures. New York: Nova Science Publishers, 2010.

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Z, Indutnyĭ I., Kurik M. V, and Institut poluprovodnikov (Akademii͡a︡ nauk Ukraïny), eds. Fotostimulirovannye vzaimodeĭstvii͡a︡ v strukturakh metall-poluprovodnik. Kiev: Nauk. dumka, 1992.

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United States. National Aeronautics and Space Administration., ed. The effect of sulfur and zirconium co-doping on the oxidation of NiCrAl. [Washington, DC]: National Aeronautics and Space Administration, 1987.

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1919-, Finlayson D. M., ed. Localisation and interaction in disordered metals and doped semiconductors: Proceedings of the Thirty-First Scottish Universities' Summer School in Physics, St. Andrews, August 1986 : a NATO Advanced Study Institute. Edinburgh: The School, 1986.

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Hallucinogens: Unreal visions. Broomall, Pa: Mason Crest Publishers, 2012.

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Rare Earth and Transition Metal Doping of Semiconductor Materials. Elsevier, 2016. http://dx.doi.org/10.1016/c2014-0-00833-7.

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Dierolf, Volkmar, Ian Ferguson, and John M. Zavada. Rare Earth and Transition Metal Doping of Semiconductor Materials: Synthesis, Magnetic Properties and Room Temperature Spintronics. Elsevier Science & Technology, 2016.

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Book chapters on the topic "Metal doping"

1

Korotcenkov, Ghenadii. "Bulk Doping of Metal Oxides." In Integrated Analytical Systems, 323–40. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-7388-6_23.

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Gurylev, Vitaly. "Strategy I: Doping." In Advancement of Metal Oxide Materials for Photocatalytic Application, 43–85. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-20553-8_2.

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Sarangan, Andrew. "Doping, Surface Modifications and Metal Contacts." In Nanofabrication, 241–77. Boca Raton : CRC Press, Taylor & Francis Group, 2017. | Series: Optical sciences and applications of light: CRC Press, 2016. http://dx.doi.org/10.1201/9781315370514-8.

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Hernández-Alonso, María Dolores. "Metal Doping of Semiconductors for Improving Photoactivity." In Green Energy and Technology, 269–86. London: Springer London, 2013. http://dx.doi.org/10.1007/978-1-4471-5061-9_13.

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Portela, Raquel. "Non-metal Doping for Band-Gap Engineering." In Green Energy and Technology, 287–309. London: Springer London, 2013. http://dx.doi.org/10.1007/978-1-4471-5061-9_14.

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Krull, Cornelius. "Doping of MePc: Alkali and Fe Atoms." In Electronic Structure of Metal Phthalocyanines on Ag(100), 115–40. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-02660-2_6.

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Jagannathan, Krishnan, Sikirman Arman, and Nerissa Mohamad Elvana. "Activation of Titanium Dioxide Under Visible-Light by Metal and Non-metal Doping." In ICGSCE 2014, 273–79. Singapore: Springer Singapore, 2015. http://dx.doi.org/10.1007/978-981-287-505-1_32.

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Kaur, Ramandeep, Rohit Dhiman, and Rajeevan Chandel. "Dual Metal–Double Gate Doping-Less TFET: Design and Investigations." In Nanoscale Devices, 159–72. Boca Raton : Taylor & Francis, a CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa, plc, 2019.: CRC Press, 2018. http://dx.doi.org/10.1201/9781315163116-8.

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Grigoryan, L. S., C. J. Liu, K. Yakushi, S. Takano, and H. Yamauchi. "Electron Doping in (Bi,Pb)-2223 Oxides Intercalated by Metal-Phthalocyanines." In Advances in Superconductivity VI, 411–14. Tokyo: Springer Japan, 1994. http://dx.doi.org/10.1007/978-4-431-68266-0_89.

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Schröder, Felicitas, and Roland A. Fischer. "Doping of Metal-Organic Frameworks with Functional Guest Molecules and Nanoparticles." In Topics in Current Chemistry, 77–113. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/128_2009_4.

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Conference papers on the topic "Metal doping"

1

PATRONOV, Georgi, Irena KOSTOVA, and Dan TONCHEV. "Influence of Samarium doping on zinc borophosphate glasses." In METAL 2020. TANGER Ltd., 2020. http://dx.doi.org/10.37904/metal.2020.3620.

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FEJERČÁK, Miloš, Karel SAKSL, Zuzana MOLČANOVÁ, Katarína ŠUĽOVÁ, Michaela ŠULIKOVÁ, Margarita RUSSINA, Veronika GRZIMEK, and Gerrit GUENTHER. "Investigation of phonon suppression by nanostructuring and doping in thermoelectric half-Heusler materials." In METAL 2019. TANGER Ltd., 2019. http://dx.doi.org/10.37904/metal.2019.754.

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Zhang, Suki N., Christopher J. Benjamin, and Zhihong Chen. "Molecular doping of transition metal dichalcogenides using metal phythalocyanines." In 2017 75th Device Research Conference (DRC). IEEE, 2017. http://dx.doi.org/10.1109/drc.2017.7999455.

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Stewart, Alexander Wyn. "Electronic Doping in Halide Perovskite Solar Cells." In Sustainable Metal-halide perovskites for photovoltaics, optoelectronics and photonics. València: FUNDACIO DE LA COMUNITAT VALENCIANA SCITO, 2022. http://dx.doi.org/10.29363/nanoge.sus-mhp.2022.001.

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Gao, Yongli. "Investigation of Doping C60 with Metal Oxide." In Advanced Optoelectronics for Energy and Environment. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/aoee.2013.asu1b.2.

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Yang, G. J., C. J. Li, C. X. Li, Y. Y. Wang, and X. C. Huang. "Effect of Copper Ion Doping on Photocatalytic Performance of Liquid Flame Sprayed TiO2 Coatings." In ITSC2006, edited by B. R. Marple, M. M. Hyland, Y. C. Lau, R. S. Lima, and J. Voyer. ASM International, 2006. http://dx.doi.org/10.31399/asm.cp.itsc2006p0853.

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Abstract:
Abstract Copper ion was added in liquid feedstock to deposit ion doping TiO2 photocatalytic coatings through liquid flame spraying. The coating microstructure was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic performance of coatings was examined by photodegradation of acetaldehyde. XRD analysis shows that the crystalline structure of coatings is not significantly influenced by the metal ion doping. The photocatalytic activity of the TiO2 coatings is enhanced by the copper ion doping. It is found that a high concentration of ion doping decreases the activity. XPS analysis shows that the adsorbed oxygen concentration is increased with the increase of Cu2+ dopant concentration and decreases with the further increase of dopant concentration. The enhancement of photocatalytic activity can be attributed to the adsorption ability of oxygen and other reactants on the surface of doping TiO2 coatings.
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Jingjing Xu, Chunyan Lai, Baofeng Wang, Honghua Ge, and Qunjie Xu. "Modification of LiNiPO4 by metal doping and carbon coating." In Environment (ICMREE). IEEE, 2011. http://dx.doi.org/10.1109/icmree.2011.5930907.

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Ramwala, Mohini, Deobrat Singh, Sanjeev K. Gupta, and Yogesh Sonvane. "Metal-Mott insulator transition of SrMnO3 by fluorine doping." In DAE SOLID STATE PHYSICS SYMPOSIUM 2016. Author(s), 2017. http://dx.doi.org/10.1063/1.4980584.

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Nag, Angshuman. "Mn- and Yb- Doping in Metal Halide Perovskite Nanocrystals." In 11th International Conference on Hybrid and Organic Photovoltaics. València: Fundació Scito, 2019. http://dx.doi.org/10.29363/nanoge.hopv.2019.054.

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Khakbaz, P., F. Driussi, A. Gambi, P. Giannozzi, S. Venica, D. Esseni, A. Gaho, S. Kataria, and M. C. Lemme. "DFT study of graphene doping due to metal contacts." In 2019 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD). IEEE, 2019. http://dx.doi.org/10.1109/sispad.2019.8870456.

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Reports on the topic "Metal doping"

1

Biefeld, R. M., A. A. Allerman, and S. R. Kurtz. The growth and doping of Al(As)Sb by metal-organic chemical vapor deposition. Office of Scientific and Technical Information (OSTI), May 1996. http://dx.doi.org/10.2172/231696.

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Jones, Robert M., Alison K. Thurston, Robyn A. Barbato, and Eftihia V. Barnes. Evaluating the Conductive Properties of Melanin-Producing Fungus, Curvularia lunata, after Copper Doping. Engineer Research and Development Center (U.S.), November 2020. http://dx.doi.org/10.21079/11681/38641.

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Abstract:
Melanins are pigmented biomacromolecules found throughout all domains of life. Of melanins’ many unique properties, their malleable electrically conductive properties and their ability to chelate could allow them to serve as material for bioelectronics. Studies have shown that sheets or pellets of melanin conduct low levels of electricity; however, electrical conductance of melanin within a cellular context has not been thoroughly investigated. In addition, given the chelating properties of melanin, it is possible that introducing traditionally con-ductive metal ions could improve the conductivity. Therefore, this study investigated the conductive properties of melanized cells and how metal ions change these. We measured the con-ductivity of pulverized Curvularia lunata, a melanized filamentous fungi, with and without the addition of copper ions. We then com-pared the conductivity measurements of the fungus to chemically synthesized, commercially bought melanin. Our data showed that the conductivity of the melanized fungal biomass was an order of magnitude higher when grown in the presence of copper. However, it was two orders of magnitude less than that of synthetic melanin. Interestingly, conductance was measurable despite additional constituents in the pellet that may inhibit conductivity. Therefore, these data show promising results for using melanized cells to carry electrical signals.
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