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1
Steele, Karl Christopher. "Evaluation of TiO2 and Ag-TiO2, CuO-TiO2 composite films for self-disinfection activity." Thesis, University of Salford, 2009. http://usir.salford.ac.uk/26923/.
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The removal or killing of microorganisms on surfaces is of concern in the health care setting, food preparation areas and general work environment. The use of TiO2 photosterilisation has been proposed as an alternative to chemical disinfection of surfaces as a means to reduce the need for increasingly concentrated and aggressive chemicals necessary to kill disinfectant-resistant organisms. The objective of this research was to evaluate the ability of photocatalytic oxidation to reduce bacterial and viral contaminants on surfaces coated with TiOa and Ag-TiC^, TiO2-Ag, Cu-TiC^, TiO2-Cu. There are no British Standards that cover evaluation of such surfaces. A method for evaluation of photocatalytic surfaces was therefore developed from BS EN 13697:2001 and used to evaluate the activities of a variety of catalytic surfaces coated with TiO2, Ag and Cu and multi-layers of Ag-TiO2,TiO2-Ag, Cu-TiO2,TiO2-Cu. The antimicrobial activities were found to be dependent on the nature of the coating. Highest killing activities were obtained with Ag and Cu alone but combinations of Ag or Cu with TiO2were more active than TiO2 alone and also retained some self- cleaning activity. The results showed that the developed method was adaptable for determination of the antimicrobial activity of coatings with a wide range of activities producing 100% killing of Escherichia coll in times from 3 min up to 4 h. The results showed that it was possible to produce self cleaning self disinfecting surfaces and that surfaces with TiO2 on top, although having reduced activity compared to Ag or Cu, were durable and may have applications in the prevention of transmission of infections on surfaces in a wide range of applications.
2
Huang, Sun-Li. "Preparation and characterization of superconducting Bi-2212/Ag composite tapes." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299820.
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Swarnakar, Prakash. "DEVELOPMENT OF NOVEL SUSTAINABLE AND ENERGY EFFICIENT NANOTECHNOLOGY FOR WATER TREATMENT." Miami University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=miami1335583032.
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Mantilla, Miguel. "Structure de films supportés : polarité de films MgO/Ag (111)- évolution de la morphologie d'agrégats Au/ TiO2(111) lors de la réaction catalytique d'oxydation du Co." Paris 6, 2009. http://www.theses.fr/2009PA066195.
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L’observation in situ de nano-objets en cours de croissance ou lors d’une réaction est un objectif important pour les nanosciences. Le présent travail porte sur deux thématiques qui relèvent de cette approche : -la croissance de films d’oxyde de magnésium MgO d’orientation polaire et -la caractérisation de films Au/TiO2(110) catalytiques. Peu de films d’orientation polaire ont été synthétisés à ce jour. La formation de films MgO par oxydation de Mg/Ag(111) est analysé ici par microscopie tunnel (STM). Les symétries 3 ou 6 excluent l’orientation MgO(100) et suggèrent l’existence de films MgO d’orientation polaire. Des hauteurs apparentes ~ 120 pm sont cohérentes avec l’hypothèse de la formation de films de structure de type NaCl orientés suivant (111). Les périodicités à longue distance qui sont mises en évidence par STM sont attribuées à des mailles de coïncidence MgO(111)/Ag(111). Très débattue, l’activité de l’or catalytique supporté dépend fortement de la taille des particules et n’est effective que pour des diamètres < 5 nm. Deux types de mécanisme sont proposés, l’un fondé sur un effet quantique associé à des particules bidimensionnelles, l’autre sur un rôle accru de la surface pour des particules tridimensionnelles de petite taille. L’objectif du travail présenté est de caractériser la les agrégats d’or in situ, pendant la réaction d’oxydation du CO, dans le cadre d’une analyse simultanée de la morphologie, de la cristallographie et de la réactivité des particules (seuls les résultats de l’étude de réactivité sont évoqués ici). Les films Au/TiO2(110) sont examinées par diffraction des rayons X aux petits (GISAXS) et aux grands (GIXS) angles. La réactivité est observable pour des agrégats de taille ≈ 5 nm et augmente au fur et à mesure que la taille des particules décroît. Il est remarquable que, même aux plus faibles tailles explorées (1,7 nm de diamètre), les agrégats d’or Au(111)/TiO2(110) sont tridimensionnels. La forte relaxation du paramètre provoquée par l’adsorption de l’oxygène démontre que l’oxygène est chimisorbé sur l’or et qu’il couvre une part significative de la surface de l’agrégat. La mise en place de la réaction catalytique qui suit l’introduction de CO provoque un mûrissement des particules, qui est attribué à l’échauffement local dû à la réaction d’oxydation, et une rotation de 4. 9° des agrégats qui témoigne de l’existence de sites préférentiels à l’interface Au(111)/TiO2(110).
5
Dias, Hércules Bezerra. "Síntese e caracterização de nanopartículas de ZnO e TiO2 dopadas com Ag para aplicação em materiais dentários." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/18/18158/tde-14012015-151052/.
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Resinas compostas comumente utilizadas em restaurações, anteriores e posteriores, resultam em maior acúmulo de biofilme bacteriano do que outros materiais restauradores, o que contribui para a formação de cáries secundárias e levam à falha das restaurações. Métodos para inibir a formação do biofilme sobre materiais restauradores dentais vêm sendo estudados há décadas e a inserção de nanopartículas (NPs) representa o que há de mais avançado nos estudos de formulação de materiais dentários antibacterianos. A literatura recente relata que resinas compostas contendo NPs de óxidos metálicos, tais como óxido de zinco (ZnO) e dióxido de titânio (TiO2), têm demonstrado capacidade antibacteriana, contribuindo para o controle do biofilme oral cariogênico. Por outro lado, a inserção dessas NPs pode alterar a cor e as propriedades mecânicas para níveis clínicos inaceitáveis e até mesmo dificultar o processo de fotopolimerização, se inseridas em grandes quantidades. Uma vez que o efeito antibacteriano e as propriedades de resinas compostas modificadas com NPs de óxidos de metais não foram amplamente estudados, esse estudo visou a compreensão destes aspectos, a partir da síntese e caracterização de nanopartículas de ZnO e TiO2 dopados ou não com Ag, inclusão em uma resina composta comercial e análise de propriedades físicas, mecânicas e biológicas do compósito modificado. As sínteses foram realizadas por diversas rotas químicas, resultando em NPs de TiO2 de alta área superficial e NPs de ZnO com morfologia tridimensional, incluindo nanoplates e nanorods que formam estruturas em formato de flores. A modificação da resina composta com NPs de TiO2.Ag alterou drasticamente a resistência à compressão do material, enquanto a adição de NPs de ZnO.Ag manteve a resistência em valores muito próximos ao da resina não modificada. A cor da resina composta sofreu grande alteração quando imergida em solução de café, especialmente após a adição de NPs de ZnO.Ag. A atividade antibacteriana, contra Streptococcus mutans da resina modificada foi considerada significativa, principalmente após a adição de 1 e 2% de NPs de TiO2. A análise dessas propriedades foi importante para o avanço das pesquisas que visam o desenvolvimento de uma resina composta antibacteriana que proporcione estética e propriedades mecânicas adequadas para a confecção de restaurações.<br>Composite resins used in restorations, anterior and posterior, resulting in greater accumulation of bacterial biofilm than other restorative materials, which contributes to the formation of secondary caries and lead to failure of restorations. Methods for inhibiting biofilm formation on dental restorative materials have been studied for decades and the insertion of nanoparticles (NPs) represents the most advanced in formulation studies of antibacterial dental materials. Recent literature reports that composites containing nanoparticles of metal oxides such as zinc oxide (ZnO) and titanium dioxide (TiO2) have demonstrated antibacterial ability, contributing to the control of oral cariogenic biofilms. On the other hand, NPS inclusion can change the color for unacceptable clinical levels and even hinder the polymerization process, if they are entered as large amounts. Since the antibacterial effect of composite resins modified with nanoparticles of metal oxides has not been widely studied, this study aimed at understanding these aspects, from the synthesis and characterization of nanoparticles of Ag doped and undoped ZnO and TiO2 NPs, inclusion in a composite business and examining their physical, mechanical and biological properties. The synthesis resulted in high surface area TiO2 NPs and three-dimensional ZnO NPs, including nanoplates and nanorods assembled flowers. The modification of the composite with TiO2.Ag NPs changed dramatically the compressive strength of the material, while adding ZnO.Ag NPs maintained compressive strength similar to the unmodified resin. The compostie color stability changed greatly when immersed in a coffee solution, especially after inclusion of ZnO.Ag NPs. The antibacterial activity, against S. mutans, of modified resin was considered significant, especially after addition of 1 and 2% TiO2 NPs. The analysis of these properties is important for the advancement of research aimed at developing an antibacterial composite that provides aesthetic and mechanical properties suitable for dental restorations.
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Rossouw, Arnoux. "Modified track-etched membranes using photocatalytic semiconductors for advanced oxidation water treatment processes." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80276.
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Thesis (MScEng)--Stellenbosch University, 2013.<br>ENGLISH ABSTRACT: The purpose of this study was to develop modi ed tract-etched membranes using
nanocomposite TiO2 for advanced water treatment processes. Photocatalytic oxidation
and reduction reactions take place on TiO2 surfaces under UV light irradiation,
therefore sunlight and even normal indoor lighting could be utilised to achieve this effect.
In membrane ltration, caking is a major problem, by enhancing the anti-fouling
properties of photocatalysts to mineralise organic compounds the membrane life and
e ciency can be improved upon.
In this study the rst approach in nanocomposite membrane development was to directly
modify the surface of polyethylenetherephthalate (PET) track-etched membranes
(TMs) with titanium dioxide (TiO2) using inverted cylindrical magnetron sputtering
(ICMS) for TiO2 thin lm deposition. The second approach was rst to thermally
evaporate silver (Ag) over the entire TM surface, followed by sputtering TiO2 over
the silver-coated TM. As a result a noble metal-titania nanocomposite thin lm layer
is produced on top of the TM surface with both self-cleaning and superhydrophilic
properties. Reactive inverted cylindrical magnetron sputtering is a physical vapour
deposition method, where material is separated from a target using high energy ions
and then re-assimilated on a substrate to grow thin lms. Argon gas is introduced
simultaneously into the deposition chamber along with O2 (the reactive gas) to form
TiO2. The photocatalytic activity and other lm properties, such as crystallinity can
be in
uenced by changing the sputtering power, chamber pressure, target-to-substrate
distance, substrate temperature, sputtering gas composition and
ow rate. These characteristics
make sputtering the perfect tool for the preparation of di erent kinds of TiO2
lms and nanostructures for photocatalysis.
In this work, the utilisation of ICMS to prepare photocatalytic TiO2 thin lms
deposited on track-etched membranes was studied in detail with emphasis on bandgap
reduction and TM surface regeneration. Nanostructured TiO2 photocatalysts were prepared through template directed deposition on track-etched membrane substrates
by exploiting the good qualities of ICMS. The TiO2-TM as well as Ag-TiO2-TM thin
lms were thoroughly characterised. ICMS prepared TiO2 lms were shown to exhibit
good photocatalytic activities. However, the nanocomposite Ag-TiO2 thin lms were
identi ed to be a much better choice than TiO2 thin lms on their own. Finally a
clear enhancement in the photocatalytic activity was achieved by forming the Ag-TiO2
nanocomposite TMs. This was evident from the band-gap improvement from 3.05 eV
of the TiO2 thin lms to the 2.76 eV of the Ag-TiO2 thin lms as well as the superior
surface regenerative properties of the Ag-TiO2-TMs.<br>AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om verbeterde baan-ge etste membrane (BMe) met behulp
van nano-saamgestelde titaandioksied (TiO2) vir gevorderde water behandeling
prosesse te ontwikkel. Fotokatalitiese oksidasie- en reduksie reaksies vind plaas op
die TiO2 oppervlaktes onder UV-lig bestraling, en dus kan sonlig en selfs gewone binnenshuise
beligting gebruik word om die gewenste uitwerking te verkry. In membraan
ltrasie is die aanpaksel van onsuiwerhede 'n groot probleem, maar die verbetering
van die self-reinigende eienskappe van fotokatalisators deur organiese verbindings te
mineraliseer, kan die membraan se leeftyd en doeltre endheid verbeter word.
In hierdie studie was die eerste benadering om nano-saamgestelde membraan ontwikkeling
direk te verander deur die oppervlak van polyethylenetherephthalate (PET)
BMe met 'n dun lagie TiO2 te bedek, met behulp van reaktiewe omgekeerde silindriese
magnetron verstuiwing (OSMV).Die tweede benadering was eers om silwer (Ag)
termies te verdamp oor die hele BM oppervlak, gevolg deur TiO2 verstuiwing bo-oor
die silwer bedekte BM. As gevolg hiervan is 'n edelmetaal-titanium nano-saamgestelde
dun lm laag gevorm bo-op die oppervlak van die BM, met beide self-reinigende en
verhoogde hidro liese eienskappe. OSMV is 'n siese damp neerslag metode, waar
materiaal van 'n teiken, met behulp van ho e-energie-ione, geskei word, en dan weer opgeneem
word op 'n substraat om dun lms te vorm. Argon gas word gelyktydig in die
neerslag kamer, saam met O2 (die reaktiewe gas), vrygestel om TiO2 te vorm. Die fotokatalitiese
aktiwiteit en ander lm eienskappe, soos kristalliniteit, kan be nvloed word
deur die verandering van byvoorbeeld die verstuiwingskrag, die druk in die reaksiekamer,
teiken-tot-substraat afstand, substraattemperatuur, verstuiwing gassamestelling
en vloeitempo. Hierdie eienskappe maak verstuiwing die ideale hulpmiddel vir die voorbereiding
van die verskillende soorte TiO2 lms en nanostrukture vir fotokatalisasie. In hierdie tesis word OSMV gebruik ter voorbereiding van fotokatalitiese TiO2
dun lms, wat gedeponeer is op BMe. Hierdie lms word dan in diepte bestudeer,
met die klem op bandgaping vermindering en BM oppervlak hergenerasie. Nanogestruktureerde
TiO2 fotokataliste is voorberei deur middel van sjabloongerigte neerslag
op BM substrate deur die ontginning van die goeie eienskappe van OSMV. Die
TiO2-BM dun lms, sowel as Ag-TiO2-BM dun lms, is deeglik gekarakteriseer. OSMV
voorbereide TiO2 dun lms toon goeie fotokatalitiese aktiwiteite. Nano-saamgestelde
Ag-TiO2 dun lms is egter ge denti seer as 'n veel beter keuse as TiO2 dun lms. Ten
slotte is 'n duidelike verbetering in die fotokatalitiese aktiwiteit bereik deur die vorming
van die Ag-TiO2 nano-saamgestelde BMe. Dit was duidelik uit die bandgapingverbetering
van 3,05 eV van TiO2 dun lms in vergelyking met die 2,76 eV van Ag-TiO2
dun lms. 'n Duidelike verbetering is behaal in die fotokatalitiese aktiwiteit deur die
vorming van die Ag-TiO2 nano-saamgestelde TMs.
7
Soliveri, G. "PATTERNING AND MODULATION OF OXIDE SURFACE PROPERTIES." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/329471.
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Most of the topics dealt with in this thesis belong to surface science. The starting point was the fundamental understanding of phenomena at the oxide-gas interface and the effect of its modification. Such knowhow was then used to solve (or, at least, to attempt to solve) issues of critical impact in everyday life: the increasing lifetime of building materials employed in low-impact smart houses; the fouling prevention in electroanalytical sensors for neurotransmitter detection; the unspecialized laboratories accessibility to microlithography, critical to device miniaturization. These challenges might seem not related, but they actually share deep scientific and technological foundations. The physicochemical modification of oxide surfaces, the creation of organic/inorganic hybrids and the exploiting / the enhancing of semiconductor peculiar properties allowed us, starting from the foundation, the realization of proof-of-concept protocols and devices, ready for the pre-commercial development.
The Leitmotif of my research was the synthesis and the modification of titanium dioxide surfaces. TiO2 has been the main character in physico, physicochemical and material science researches of the last 50 years. Biocompatibility and low cost make it engaging for many applications. Its (near-UV active) semiconductor features, well known and abundantly investigated by the scientific community, are acquiring central interest also in many markets with the development of self cleaning coatings, windows and asphalts, anti-fogging mirrors and self-sterilizing surgery rooms and instrumentations. New generation batteries and solar cells are going to be developed as commercial prototypes. One of the biggest challenges in the titania fundamental research is the enhancement of activity in the solar spectrum. First, the most recent aspects in titania doping and promotion were touched. While, in the last twenty years, great effort has been made in the mono-atomic doping of titania and in the understanding of the influence of the dopant position in the titania lattice and its electronic behavior, the most recent literature describes the co-promotion of the material by two (or more) atoms doping. The metal/non-metal codoping seems especially promising; the synergetic effect of the two atoms in the TiO2 lattice was both theoretically and experimentally proved. In this contest, the N/Nb codoping was analyzed, investigating the effect of the atoms in the lattice from morphological (surface area, porosity and crystallographic structure) and electronic point of view (EXAFS, UV-Vis absorption and EPR analyses). N/Nb codoping was compared with N/Ta co-doped samples, synthesized by two different procedures. The photoactivity of the two sample families was tested by a model reaction (the degradation of ethanol, throughout acetaldehyde intermediate) both under UV and solar simulated irradiation.
Then, a different approach in the modification of surfaces was tested. The assembly of organic/inorganic hybrids was tested; thanks to the formation of organic mono- or multi-layers at the surface,they can tune the chemistry, the polarity and the adhesion properties of the interface. Siloxanes were used as active agents, thanks to their compatibility with oxide materials and, especially, for the ability to self-assemble at the surface to form a monolayer. Siloxanes are able to react with the -OH groups at the surface, chemisorbing and polymerizing at the interface in such a way to form a monolayer with tunable functionalities. Many different silanes were tested and their dipole momenta were related to their wettability properties. Such siloxanes chemisorb strongly both from the gas phase and the liquid phase. Their reactivity, both on smooth and rough surfaces, was tested vs the temperature of functionalization in gas phase. Many characterization techniques were adopted to understand the behavior of such molecules from a molecular point of view: magnetic (solid state NMR), microscopic (SEM, TEM, AFM), optical and electrochemical (CV and EIS). The science of adhesion and wettability was also adopted for the development of superhydrophobic coatings. Titanium dioxide particles with engineered morphology were used as the best candidate to create superhydrophobic/superhydrophilic patch-wise surfaces, exploiting their photoactivity (photolithograpy).
The core of the thesis was the synthesis, modification and application of transparent photoactive thin films. A procedure for the synthesis of smooth, transparent and photoactive TiO2 thin layers was developed, and used to produce highly applicative devices and protocols. Such synthetic strategy is highly tunable and reproducible; the obtained films are robust and active and, most of all, require simple instrumentation (sol-gel procedure), which is highly appealing for the market. The films were properly characterized both form the morphological/mechanical and photochemical point of view. Apart their transparency and their thickness, the films were highly crystalline (pure anatase phase). Such procedure was firstly designed as a proof-of-concept for self-cleaning windows, but, thanks to its versatility and the high activity of the films, it leads the path towards highly applicative procedures and devices. The smoothness and the photoactivity brought me to the field of photolithograpy, especially in the direction of microlithography. The high activity of the titania allowed the use of safe and low-energetic lamps. No collimation was required to obtain a resolution lower than 5 µm. First of all, I tested the lithography on siloxane monolayer films, as a proof-of-concept of resolution and efficiency. But siloxanes, as many other self-assembled monolayer molecules, can be the pillars for 3D fabrication. Such monolayers were used as polymerization initiators for polymer brushes. If the initiators of polymerization are patterned, patterned polymer brushes will be obtained. That was the first report of polymer-brushes lithography exploiting the photoactivity of TiO2. Remote photocatalytic lithography makes this procedure extremely versatile. Exploiting the remote photocatalysis, in principle, any material can be used as a support for patterned polymer brushes growth (provided that the initiator are able to graft the surface).
The developed protocol for the synthesis of TiO2 thin films was also used to design and engineer complex electrodes for cyclovoltammetric analyses of biological samples. Electrochemistry seems to be the best candidate for the development of an analytical option with sensitivity comparable with present analytical procedures but reduced time-per-analysis and cost. Unfortunately, catecholamines chemisorb and polymerize on metal and oxide electrodes quickly, making the device useless. Covering the electrode by a homogeneous, nano-porous thin layer of titania makes the surface photoactive. That is the first example in literature of self-cleaning nano-engineered electrodes for cyclic voltammetry. After the detection, also in simulated human serum and liquor, a fast and simple irradiation of the device, under non-hazardous UV-A lamp, degrades all the fouling on the surface without altering its features. The sensor, after each UV treatment, recovers its pristine performances, with full recovery in terms of selectivity and sensitivity. Irradiation trials were also performed directly in the analytical mixture, as a proof of concept for on-site application.
Modern era requires flexible and light materials for the building industry. Polymers are acquiring more and more interest thanks to their increasing performances and their smart properties. The drawbacks of such materials are connected to the low resistance to the UV light, the softness and the difficulties in cleaning procedure. The use of organic/inorganic hybrid, or better the coverage of plastic materials with an oxidic thin layer, can solve many of these problems, lengthening the lifetime of such materials. If the covering oxide is also photoactive, the material can be self-cleaned when exposed to solar light. That is a big chemical challenge, because of many synthetic problems. Two different approaches were tested to solve this relevant issue. On one side, the hydrophobicity of ionic liquid modified SPES (sulfonated polyether sulfone) was combined with designed morphological features to confer superhydrophobicity. On the other side, the polymeric surface was covered with a transparent titania layer active in the near UV-region, able to mineralize organic molecules chemisorbed at the surface.
Eventually, a different approach to modify oxidic (and not only) surfaces is the creation of a homogeneous layer of Ag nanoparticles by an innovative microwave procedure. That simple and accessible strategy allowed us to produce plasmonic surfaces (thanks to the dimension and the homogeneity of the Ag particles) with countless applications. The layer was shown to be a very active substrate for surface enhancement Raman spectroscopy (SERS). Thanks to the versatility of the synthetic method, all shapes and dimensions can be covered. That makes it a perfect candidate for the production of new generation of SERS sensors. The sensitivity towards molecules of environmental and biomedical interest was proved.
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Lin, Chi-Feng, and 林奇鋒. "Preparation of Ag-TiO2 composite films by magnetron sputtering for its visible light photocatalytic applications." Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5159038%22.&searchmode=basic.
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碩士<br>國立中興大學<br>材料科學與工程學系所<br>107<br>In order to solve the energy shortage and environmental pollution caused by economic development and rapidly exacerbation of the environment, Photocatalyst materials which use solar energy as a direct driving force are attracting attention.
Photocatalysis can transfer low-density solar energy into high-density chemical energy. This experiment incorporates nanosphere template and magnetron puttering techniques to prepare TiO2/Ag hollow sphere composite film structure. By applying proper coating conditions, we could manufacture a stable film containing titanium dioxide combine with silver particles. And the bilayer nanofilms can increase specific surface area by hollow sphere structure which could extends absorption of visible light and promote photocatalytic degradation.
The experimental process is to annealing in vacuum after establishing three-dimensional structure, so that the silver agglomerate particles are dispersed in the amorphous titanium oxide, and the failure caused by oxidation or sulfurization is avoided. By the characteristics of silver nanometer particles agglomerated on the free surface after annealing, it could promote the reaction with degradation solution methylene blue (MB). Noble metal silver increases the ability to absorb visible light in the surface plasma effect (SPR), moreover, it can increase the induced carrier by photo, and enhance the photocatalysis application in the visible region.
In order to enhance the light capturing ability of photocatalyst film, high visible light absorption rate film was selected for preparation in this experiment. Through experiments we found that the co-sputtered film of TiO2/Ag under 15 W of silver target, the light absorption does not change with substrate temperature, and still maintain good absorption rate. In particular, the TiO2/Ag multilayer film with periodic thickness 2 nm, the surface morphology particle are uniform and particle agglomeration is significant, which maintains a large amount of contact surface area. Using Nano sphere template to construct hollow spherical film, and then carried out photocatalysis degradation experiment, we expect this could be made for excellent photocatalyst materials.
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Chi, Chung Yang, and 紀重仰. "Preparation of Nanosized Ag/ TiO2 Composite Films from the Sawdust Extract for Photocatalyst and pH Sensor Applications." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/mk584g.
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碩士<br>國立虎尾科技大學<br>材料科學與綠色能源工程研究所<br>101<br>There are four parts in this study. Firstly, we report how to extract the furfural solution using 5N sulfuric acid (H2SO4) solution is obtained from the Chamaecyparis obtusa var. formosana and Cinnamomum camphora sawdust materials for the preparation of chemical plating silver on a titanium oxide film (TiO2), respectively. The qualitative analysis of furfural is used by silver mirror reaction. Titanium oxide film is manufactured by anodization in 0.5 M sulphuric acid solution, titanium foil as anode and platinum as cathode at room temperature under 15 V constant potential conditions. Titanium substrate anodized was placed in a mixed solutions at reaction time of the 8 and 15 minutes under the temperature of 30 ~ 35 ℃for the silver coating by the chemical plating, respectively. After the deposition, the Ag/TiO2 film is investigated by the XRD analysis and the surface morphology of Ag/TiO2 electrodes is observed by the FE-SEM.
Secondly, the corrosion behavior of the Ag/TiO2 film is investigated in a simulated polymer electrolyte membrane fuel cell (PEMFC) environment included 0.5 M H2SO4 solution at room temperature. Potentiodynamic polarization test is performed to determine the corrosion properties of chemical Ag plating. It was found that corrosion potential of the coated sample at room temperature was shift toward noble potential and corrosion current density decreased.
Thirdly, the photocatalytic degradation of dyeing agent for acid orange 7 (AO7) at 10 ppm concentrations by the Ag/TiO2 film were carried out under 400W UV radiation for 4h respectively. Spectrophotometer confirmed that concentration was greatly reduced.
Fourthly, use the prepared Ag/TiO2 electrodes under pH 2, 4, 7 and 10 standard solutions to test the potential sensing performance of different concentration of hydrogen ion, respectively. Through the mathematical analysis the hydrogen ion diffusion coefficient is determined. For pH 2 and 4 the hydrogen ion diffusion coefficients are 10-2~10-6 order. However, for pH 7 and 10 are 10-11 order. These results indicate that the prepared sensors have good response time and stable ability in the standard solutions. Experimental results show that the Ag/TiO2 electrode is suitable for PEMFC bipolar plate, Photocatalyst and pH sensor applications.
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Li, Ke-Zhong, and 李可中. "Polyol Mediated Synthesis of Ag Nanowires Applied to Transparent Conductive Films and Ag Nanowires-TiO2 Composite Photoanodes for Dye-Sensitized Solar Cells." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/zzb5u2.
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碩士<br>國立宜蘭大學<br>化學工程與材料工程學系碩士班<br>107<br>Among the many metal nanomaterials, the development of silver nanowire is the most vigorous, the stability of silver is stable and the surface is not easy to be oxidized. Especially in the application of silver nanowire, it is widely studied in emerging fields. We used the polyol method to synthesize silver nanowire, and the size of the silver nanowire was controlled to obtain better optical, electrical and thermal properties.
In this study, the silver nanowire was prepared by polyol synthesis. The silver nitrate was first dissolved in ethylene glycol to form a silver nitrate-ethylene glycol solution. Under heating, the silver nitrate-ethylene glycol solution was added to the PVP-ethylene glycol solution. The silver ions are reduced to silver nanoparticles, and PVP is used as a blocking agent, passivated the (100) plane of the silver causes silver to grow into a silver nanowire. The results show that when the reaction temperature is 170 ℃ and the molar ratio of silver nitrate: PVP = 1:3, the diameter of silver nanowires can be controlled below 50 nm, and the length above 25 μm, respectively, and the aspect ratio is 460. In this study, a synthetic one-dimensional silver nanowire was applied to transparent conductive films and a dye-sensitized solar cells. In the silver nanowire transparent conductive films, the silver nanowire forms a mesh-shaped conductive network in an overlapping manner, and the mesh structure hole can penetrate the light to achieve the effect of transparency and conductivity. In addition, in this study, the silver nanowire was coated on a transparent substrate by spin coating, the concentration was reduced and the coating was repeated to increase the light transmittance and conductivity, then filling the holes in the network structure of silver nanowire with PEDOT:PSS, and the conductive film has a light transmittance of 80% and having a resistance of 10 Ω.
The addition of silver nanowires increases the photoelectric conversion efficiency of dye-sensitized solar cells. Due to the surface Plasmon Resonance (SPR), the surface of the silver nanowires can expand the wavelength of light absorption, increase the use of light, and excited more electrons of dye molecules, one-dimensional structure can provide electron directionality. The results show that the optimized electron transport when adding 0.3 wt% silver nanowire in titanium dioxide increases the short-circuit current density to 14.83 mA/cm2 and the photoelectric conversion efficiency reaches 7.92%.
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Yu, RueiBin, and 尤瑞彬. "The structures and photocatalytic properties of TiO2, TiO2-Ag,TiON, and TiON-Ag thin films." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/40002946149354328229.
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碩士<br>明志科技大學<br>材料工程研究所<br>99<br>TiO2, TiOxNy thin films have been deposited on unheated glass substrates by a direct current (dc) reactive magnetron sputtering. TiO2-Ag, TiOxNy –Ag thin films were prepared using reactive co-sputtering with Ti and Ag targets on silicon substrates and Corning glass substrates. These films were annealed in Ar atmosphere, at 300 oC, 400 oC, 500 oC, 600 oC, 700 oC, and 800 oC. The studies on microstructural, optical, light degradable, anti-bacterial properties for TiO2-Ag, TiOxNy -Ag nano-composite films were then carried out. The films structures were examined with X-ray diffractometry, TEM (transmission electron microscopy), FESEM (field emission scanning electron microscopy). As for the optical properties, UV-Vis-NIR, PL spectrometry were used. Finally, hydrophilic test and MB degradation test were carried out to test the photocatalytic properties of these films.
The results show that the absorption of the Ag-doped films would increase in the visible-light range. Some of the increase is clearly due to plasmon resonance effect. All Ag-doped TiOxNy are hydrophilic under visible light irradiation. As for the change of microstructure, Ag-doped TiO2 leads to amorphous structure. After being annealed at 500 oC, the films tend to become anatase phase first due to its fine grain structure. When the annealing temperature increased to 800 oC, the phase tends to become rutile. Ag-doped TiO2 and TiOxNy films are found to inhibit the recombination of electron-hole pairs. However, when the Ag contents reach a certain limit, no enhancement can be found. This is probably due to the light blocking effect.
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Huang, Ya-Hui, and 黃雅惠. "Effects of Ag/TiO2 composite nanoparticles on mammalian cells." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/20057048137429884325.
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碩士<br>高雄醫學大學<br>生物醫學檢驗學研究所碩士班<br>94<br>Photoexcited titanium dioxide can be used to kill microorganisms by the resulting free radical activity. Nanosized silver/TiO2 composite would enhance the catalytic efficiency of photoexcitation. However, the possible effects resulted from photoexcited Ag/TiO2 nanoparticles on mammalian cells remain to be elucidated. To investigate the photocatalytic cytotoxic effects of photoexcited Ag/TiO2 nanoparticles on mammalian cells, four mammalian cell lines including 293T (human emoryonic kidney) , Vero (Monkey kidney normal cells), A549 (Human lung epithelial of carcinoma cells) and MDA-MB 231 (human breast cancer cells) were tested for cell viability and oxidative damage assay. After exposed the cell to photoexcited Ag/TiO2 nanoparticles for 24 and 48 hours, the cell morphology was examined using transmission electron microscopy and cellular toxic response was measured by measuring cell viability based on trypan blue test. In addition, to assess the extent of oxidative damage, malondialdehyde (MDA) in the cell medium was measured using HPLC method. The results showed that Ag/TiO2 nanoparticles could be observed in the cytoplasma of the four mammalian cellsMoreover, the cell viability of MDA-MB 231 cells decreased significantly (p<0.05) after 24H irradiation of UVC light on the composite nanoparticles of Ag/TiO2 solution for 2 minute, while the viability of Vero cells decreased after 48H irradiation of UVC light on the composite nanoparticles of Ag/TiO2 solution for 14 minute. MDA levels in the suspension of 293T, Vero and MDA-MB 231 cell lines were found to be elevated after irradiation for Ag/TiO2 nanoparticles. In summary, based on the results obtainedthe composite nanoprticles of Ag/TiO2 have potential cytotoxic effects on mammalian cells under UV irradiation.
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Lin, Wei-Lian, and 林緯良. "The TiO2 powder preparation, and the mechanical properties and microstructure of TiO2/Ag composite." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/48149211328412288965.
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碩士<br>國立臺灣大學<br>材料科學與工程學研究所<br>87<br>The brittle nature of ceramics is the most serious problem in many applications. To improve the toughness of ceramics, ductile metallic inclusions are introduced into the ceramics. In the present study, homemade TiO2 and commercial TiO2 powder was used to prepare the TiO2/Ag composite. The sintering behavior, microstructure and mechanical properties were investigated.
In the first part of the present study, the homemade TiO2 powders were synthesized with the yield above 80% by the thermal hydrolysis of TiCl4 in a mixed solvent of n-propanol and water. The precipitates obtained with an RH ratio (volume ratio of n-propanol to water) of 0 are strongly agglomerated, and larger than that of the agglomerates of the precipitates obtained with an RH ratio of 3. Also, the yield of the RH = 3 precipitates is up to 81% and is much higher than that of the RH = 0 precipitates. The extent of crystallization (anatase phase) of the RH = 3 precipitates is also better than that of the RH = 0 precipitates. Both the RH = 3 and RH = 0 precipitates are nearly spherical and with narrow size distribution. The size of the primary particles and agglomerates is 4 and 25-50nm, respectively. The result of the FTIR (Fourier transformed infrared) spectroscopy showed the chemical interactions are taken place between TiO2 particle surface and n-propanol, which increase the yield and the extent of crystallization of the precipitates and decrease the anatase-rutile transformation temperature of the precipitates. Because of the precipitates of the homemade TiO2 are fine and highly agglomerated. The specimens composed of the as-precipitated TiO2 can not be densified even after sintering at 1300℃ for one hour. By ball milling and AgNO3 coating, the large agglomerates can be destroyed. Then, the relative density of the specimens reaches 97% after sintering at 1300℃ for one hour. The existence of the Ag inclusions inhibits the grain growth of TiO2. The plastic deformation of the Ag inclusions can be observed on the fracture surface of the composites. Therefore, the addition of Ag particles may toughen the TiO2.
In second part of the present study, the TiO2/Ag composites were prepared by using a commercial TiO2 powder, which with mean particle size of 1.56m. The composites were prepared by sintering at 1300℃ for one hour. The wettability of the liquid Ag is good to TiO2 matrix. Therefore, with a small addition of Ag particles, the density of composites can be increased. The relative density of the composites containing 7.7vol% Ag is 99.3%. The Ag inclusions inter-connected in the composite when the Ag content is higher than 7.7vol%. The flexural strength is affected by the density and the TiO2 grain size of the composite. However, the flexural strength of all the composites is higher than that of the TiO2 specimens even as the relative density of the composites containing 13.9vol% is only 91.6% (the relative density of the TiO2 specimens is 96.7%). The fracture toughness is affected by the inter-connectivity of Ag inclusions and the inclusion size. The flexural strength and fracture toughness of the composites containing 7.7vol% Ag is respectively 1.4 and 1.9 times that of TiO2 specimens.
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Chen, S. Y., and 陳尚煜. "Anomalous positive magnetoresistance in Fe3O4-Ag composite films." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/32506591733627718248.
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碩士<br>國立臺灣大學<br>物理學研究所<br>89<br>Abstract
The anomalous positive magnetoresistance effect of Agx-(Fe3O4)1-x composite films have been investigated. Samples were prepared by dc magnetron sputtering with composite targets and the Si(100) wafer was used as the substrate.
We have studied the composition, structure, and morphology of Agx- (Fe3O4)1-x composite films by EPMA, X-ray diffraction and SEM respectively. The resistivity of Agx-(Fe3O4)1-x films were measured by four-probe method. The MR was in general obtained with a maximum applied magnetic field of 0.8 Tesla at 350K, 300K and 225K. The value of MR ratio is defined to be MR={R(H)-R(0)}/R(0). The magnetic properties of the films were determined with SQUID between 150K and 350K.
It has been found that a negative magnetoresistance of about 0.3% is observed for pure Fe3O4 films. With the incorporation of a small amount of Ag nanoparticles into Fe3O4 matrix, the MR value suddenly becomes positive. The MR ratio reaches a maximum value of about +0.5% at x=0.007. The positive MR effect disappears at x≒0.015. The MR value re-entries into negative region again. Furthermore, its magnitude is decreasing with increasing x. If the contribution from the negative MR effect of Fe3O4 and the OMR effect of Ag are subtracted, the anomalous positive magnetoresistance is present only in a very narrow region between 0.001＜x＜0.02. At x=0.02, the average granular size of Ag is about 10nm.
This phenomenon of extra anomalous MR can be explained from spin current injected into Ag granules, inducing spin accumulation inside Ag granules. Therefore, using MR measurement, the spin diffusion length at room temperature in Ag particle was determined to be 9nm. And as the temperature decreases to 225K, the spin diffusion length increases to 10nm.
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Wang, Chia-Wei, and 王嘉緯. "Photocatalysis of Ag-Loaded TiO2/Poly(L-Dopa) Multilayer Films." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/e823f8.
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Lin, Shiau-Mei, and 林筱玫. "Fabrication and Characterization of TiO2/Ag/TiO2 Multilayer Films and Their Application to Photodetectors." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/4347hh.
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碩士<br>國立虎尾科技大學<br>光電與材料科技研究所<br>99<br>Titanium dioxide is the good material of semi-conductor. It has good chemical stability, non-toxicity, low cost, and high photocatalysis. However, the wide energy has band gap (3.2eV) and it’s excited only by ultraviolet range, pure TiO2 has very low photocatalytic efficiency. This study is attempted to deposit by precious metal and decreases the band-gap of TiO2. It was in order to raise the optical absorption properties in visible region and was in hope to improve the performance of photocatalytic properties and conductivity. The first part is that a TiO2/Ag/TiO2 nano multilayer film was grown on Corning glass substrate. It was used radio frequency (rf) magnetron sputter system and electron gun evaporator system. Ag film with approximately 12 nm is the thinnest single layer continuously from the experimental results. We could investigate the optical and electrical performance of TAT structure by transform TiO2 thin film. FE-SEM and AFM were used to characterize the surface morphology and UV-VIS transmittance spectra (UV-VIS) examine transmittance of the TAT nano multilayer films.
The second part is we could fabricate the Ti/Au electrodes of PDs with optimization of TAT structure and discuss about the characteristic. It can be found that dark current of different structure MSN-PDs were 2.07 nA (TiO2) to 82.5 nA (TAT) at 5 V bias. We could observe that conductivity of TAT structure has increase.
The third part is we discuss and demonstrate that TiO2 nanorod arrays were prepared on TiO2 and TAT seed layer by the chemical bath deposition has approached. The morphology of optical and electrical performance was obtained TiO2 nanorod arrays investigation for the different seed layer. Additionally, PDs with nanorod arrays have been fabricated and characterized.
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Kao, Shih-Mou, and 高釋懋. "Effect of seeding to crystallization of solvothermally prepared anatase TiO2 and TiO2/Ag composite particles." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/21693247780997689457.
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Chang, Yu-Sung, and 張寓淞. "Structure and optoelectronic properties of TiO2/Ag/TiO2 transparent conductive films prepared by magnetron sputtering." Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5159027%22.&searchmode=basic.
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碩士<br>國立中興大學<br>材料科學與工程學系所<br>107<br>Oxide semiconductor TiO2 has good optical properties and mechanical stability at room temperature, and is widely used in transparent electrodes in components. Ag is a good electrical conductor and the metal with the lowest conductivity. Interspersing a layer of Ag in the TiO2 film can effectively reduce the resistivity of the transparent conductive film, and can be made into a very thin transparent conductive film (thickness less than 100 nm). Therefore, it has better flexibility. In order to avoid the deterioration of the photoelectric properties of the Ag layer due to high temperature, this study is divided into two major directions. The first part is to change the film thickness to investigate the photoelectric properties, and the second part is to change the substrate temperature and retreat. The underlying TiO2 film was annealed at atmospheric and the properties of the film were observed.
In the first stage of the experiment, the thickness of the lower TiO2 on the TiO2/Ag/ TiO2 was changed, and the effect of the thickness of the intermediate layer on the film properties was observed. It was found that the high visible light transmittance of 88.22% and low resistance in the upper and lower TiO2 thickness of 40 nm. The rate is 5.909×10-5 Ω-cm, and the high figure of merit is 38.73 mΩ-1. When the thickness of the intermediate layer Ag of TiO2/Ag/TiO2 is changed and the thickness of the upper and lower layers of TiO2 is fixed, the FCC structure of Ag and the short-range ordered structure of TiO2 appear. The resistivity decreases with the increase of thickness, and the best is obtained when the thickness is 10 nm. The high figure of merit, at this time, the visible light transmittance and low electrical resistivity are about 88% and 5.458×10-5 Ω-cm, respectively. Then, the thickness of TiO2/Ag/TiO2 is 40 nm/10 nm/40 nm, and the average visible light transmittance is about 88% and the low electrical resistivity is 5.458×10-5 Ω-cm and the high figure of merit is up to 45.8 mΩ-1.
In the second stage of the experiment, TiO2/Ag/TiO2 was used for sputtering and the substrate temperature, atmospheric annealing and underlying TiO2 annealing were observed to observe the change of film properties. When Ag was used as the intermediate layer, the agglomeration phenomenon became more and more obvious with the increase of substrate temperature. When it is raised, the photoelectric properties of the film are deteriorated, and the color of the film is blue. At atmospheric annealing, the high figure of merit is 95.08 mΩ-1 at 300 °C. At high temperature, oxygen diffusion to the Ag layer forms silver oxide. The photoelectric properties are invalid, and the color of the film is yellow. Finally, in the atmospheric annealing of the bottom TiO2, the high figure of merit is 85.56 mΩ-1 at 400 °C.
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Liao, Yu Han, and 廖于涵. "Preparation and Photocatalysis of TiO2/Cellulose Nanofibers Composite Films." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3y2t2u.
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Chuang, Yi-Chen, and 莊宜蓁. "Synthesis and property of functional Fe3O4@Ag@TiO2 core/shell composite particles." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/52552706585723251910.
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碩士<br>國立中興大學<br>材料科學與工程學系所<br>103<br>Functional Fe3O4@Ag@TiO2 core@shell composite particles have been prepared through chemical reduction and solvothermal routes. Magnetic Fe nanoparticles were synthesized by chemical reduction in water with sodium borohydride (NaBH4) as a reducing agent over a range of reaction temperatures and sodium citrate (Na3C6H5O7) concentrations as a protective agent. At room temperature, an optimal Na3C6H5O7 concentration of 1.67 mM was determined for synthesizing the magnetic Fe nanoparticles. Fe@Ag core@shell particles were then synthesized by heterogeneous nucleation and oxidation-reduction method. We have adjusted the injection time and concentration when silver nitrate was added into a reaction vessel containing the Fe particles. We found that when 15.4 mM of AgNO3 was added into the Fe-containing solution after 10 minute, Ag was part of a continuous film coated on the surface of the Fe particles. We then used 2-mercaptoethanol monolayers to facilitate formation of a TiO2 coating layer on the surface of Fe@Ag particles. The Fe@Ag core@shell particles were modified with different concentrations (0.1~2%) of 2-mercaptoethanol adsorption isotherm revealed that the Langmuir monolayer behavior resulted. When the concentration of 2-mercaptoethanol was 0.5 wt% a saturated adsorption capacity was obtained. Finally, coating of mesoporous TiO2 (m-TiO2) film on the Fe@Ag surface was carried by solvothermal method. The amount of Titanium (IV) butoxide (TBOT) was adjusted from 0.25 to 2.5wt%, which led to m-TiO2 shell with an increasing thickness. When the TBOT amounted to 2.5 wt% the m-TiO2 shell thickness was up to 50 nm.
The Fe3O4@Ag@TiO2 core@shell composite particles showed a BET surface area of 340.7 m2g-1 and a BJH average pore diameter of 5.2 nm. SAXRD and HRTEM observation revealed that most of the pores in the m-TiO2 were disorder similar to the worm-hole structure with partly of short-distance regularity. The magnetic properties were examined by superconducting quantum interference magnetometer (SQUID) at room temperature. The saturation magnetization (Ms) was at 50.33 emu/g.
The photocatalyst efficiency exhibited a selective affinity in different environments under UV irradiation. In an acidic environment, photocatalytic effect of methyl orange (MO) was more significant than that of methylene blue (MB); on the contrary, photocatalytic of MB the catalytic effect is obvious in an alkaline environment. Bactericidal efficiency of the Fe3O4@Ag@TiO2 core@shell composite particles against E. coli was 71% after 24h.
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Lin, Chun-Wei, and 林君緯. "Fe3O4@Ag@TiO2-xNx Composite Particles for Dye Adsorption, Visible-Light Photocatalysis, Magnetic Recycle, and Ag Discharge." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/01453299784998020961.
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碩士<br>國立中興大學<br>材料科學與工程學系所<br>105<br>Nitrogen-doped Fe3O4@Ag@TiO2-xNx composite particles have been successfully synthesized by solvothermal method using different kinds of dopant including methylamine (MA), diethylamine (DEA), ethyleneamine (EDA), urea (U), and ammonia (A). X-ray diffraction revealed that diffraction peaks pronouncedly broaden and their intensity reduce with the N-doping, indicating that reduced crystallinity and smaller crystalline size resulted. Based on XPS analysis, interstitial nitrogen-doping was found in the titanium dioxide layer of the composite particles. The Fe3O4@Ag@TiO2-xNx composite particles exhibited a high BET surface area of 251.3~431.9 m2/g and a BJH average pore diameter below 10 nm. By SQUID measurement at room temperature, the saturation magnetization (Ms) of the particles was 0.02 emu/g. From UV-vis spectroscopy and Tauc plot, the band gap was determined in the range of 2.4-2.8 eV for the Fe3O4@Ag@TiO2-xNx composite particles. We have also investigated dye degradation of organic dyes in water by dark adsorption and visible light irradiation. Among the nitrogen sources examined, the as-prepared powders show different adsorption ability to methylene blue (MB) and methyl orange (MO) as the solution pH was altered. The dye molecules must be adsorbed on the powder surface, before being photodegraded under the light irradiation. The methylamine-doped particles were found to have ~90% adsorption for the MB dye at pH=2, and ~30% adsorption followed then by ~20% photocatalytic activity for the MO dye. At pH=9, the methylamine-doped ones showed ~100% adsorption for the MB dye but there was no adsorption for the MO dye. The urea-doped ones showed ~40% adsorption followed then by ~30% after visible light irradiation at pH=2, but there was no significant effect for the MO degradation. In addition, the initial dye concentration was varied, and the methylamine-doped composite particles appeared to exhibit a multilayer adsorption behavior when the dye concentration was below 2.5x10-5 M. The methylamine-doped powders were recycled by an external magnetic field and were re-used for the dye removal. The particles showed a degradation rate nearly 95% after up to five times of use. Finally, Ag could be slowly released from the composite particles through the mesoporous shell structure. The release of Ag was found after immersion in water for 48 h, indicating long-lasting bactericidal ability.
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Huang, Lin-Nan, and 黃霖楠. "Humidity sensors based on TiO2 nanoparticles/polypyrrole composite thin films." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/31264067468887360756.
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碩士<br>中國文化大學<br>應用化學研究所<br>96<br>Resistive-type humidity sensors were fabricated through in-situ photopolymerization of pure polypyrrole (PPy) and polypyrrole/TiO2nanoparticles (PPy/TiO2 NPs) thin film on an alumina substrate. The thin films were analyzed by Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive spectrometer.
The electric properties of humidity sensors were investigated based on addition of silver nitrate and TiO2 NPs and lighting time. In addition, we also discuss the basic humidity sensing properties, such as temperature effect, applied frequency effect, response and recovery time and long-term stability.
The humidity sensing mechanism of TiO2 NPs/PPy composite thin films was investigated via the results of activation energy and impedance spectroscopy.
Keywords: Humidity sensor; In situ photopolymerization; Composite film; Polypyrrole; TiO2 NPs; Sensing mechanism
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Yu, Chun-Huang, and 尤俊煌. "Characterization of TiO2-SiO2 composite oxide films as gate dielectrics." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/24578557708418187908.
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碩士<br>國立成功大學<br>材料科學及工程學系碩博士班<br>91<br>The material characterizations of various TiO2-SiO2 composite oxide thin films prepared with low pressure chemical vapor deposition, using titanium tetra-iso-propoxide(TTIP) and tetraethoxysilane(TEOS) as precursors, before and after annealing were investigated. The characterizations of TiO2-SiO2 composite thin films as gate dielectrics were investigated by I-V and C-V measurement.
In this study, Rutherford backscattering spectrometry (RBS) analysis was used to determine the composition of TiO2-SiO2 thin films. The structure and crystallography of the composite oxide thin films were characterized by glancing incident angle X-ray diffraction (GIAXRD) and transmission electron microscope (TEM) diffraction patterns. The morphology of TiO2-SiO2 thin films before and after annealing were observed with scanning electron microscope (SEM) and transmission electron microscope (TEM). The chemical bonding of TiO2-SiO2 thin films were investigated with X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Spectroscopic ellipsometry was carried out to measure the refraction index and thickness of TiO2-SiO2 thin films. Finally the electrical properties (I-V, C-V) were measured by PA meter /dc voltage source(HP4140) and LCR meter(HP4284).
From RBS results, the composition ratios of Si/(Ti+Si) in the oxide thin films increased with the increasing carrier flow rates through TEOS. However, the stoichiometry of (Ti+Si):O maintained 1:2 for all films. Pure TiO2 thin film revealed the anatase phase before and after annealing. The as-deposited composite oxide thin films with altering SiO2 ratios were amorphous. The composite oxide thin films with altering SiO2 ratios crystallized after annealing at 600, 700, and 800℃, but the diffraction intensities were much smaller compared with pure TiO2. The morphology of TiO2-SiO2 composite thin films were much smoother than pure TiO2 thin films before and after annealing. The binding energy of O 1s core level electron of TiO2-SiO2 composite thin films were shifted to lower energy as the SiO2 ratio in the composite thin films increased. The binding energy of Ti 2p and Si 2p of TiO2-SiO2 composite thin films remains constant with different SiO2 ratio. The intensity of FTIR signal were much stronger after annealing, indicating that the atoms in the annealed thin films were arranged much uniformly than those as-deposited. The refractive indexes decreased by increasing SiO2 ratio in the thin films. The relative dielectric constants were almost the same with various SiO2 ratios after 600 and 700 ℃ annealing. The relative dielectric constants of high SiO2 composition were smaller than the pure TiO2 films after 800℃ annealing. The leakage current densities decreased as annealing temperature increased. The leakage current densities of various TiO2-SiO2 composite thin films did not exhibit an obvious tendency with the ratio of SiO2 in the thin films.
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Chen, Yan-Hao, and 陳彥豪. "Ag particles/In2O3 composite phase by oxidizing Ag-In alloy films and photocurrent characteristics of Ag particles/In2O3." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ujpzxm.
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博士<br>國立中央大學<br>化學工程與材料工程學系<br>106<br>The aim of this research is to investigate the photocurrent characteristics of Ag particles/In2O3 Ohmic contact. The Ag particles/In2O3 Ohmic contact was fabricated by Ag-In alloy film with different composition heat-treating at 800 oC in oxygen ambience. The contact of Ag and In2O3 is confirmed be Ohmic contact. Photocurrent characteristics of Ag particles/In2O3 composite structure was researched by using illumination light with different photo energies. Since the photo-carrier generation is determined by the optical generation rate and recombination lifetime (Δn = geτr), the discussion will be focused on these two factors.
The results show that under UV-light illumination, the photocurrent of pure In2O3 thin film with the oxygen adsorption could be enhanced. The mechanism has been reported that surface oxygen adsorption would induce a surface build-in electric field and enhance the life-time of excited electron-hole pairs, which would enhance life time. However, the photocurrent of the Ag particles/In2O3 fabricated by oxidized Ag70In30 alloy film is two orders higher than that of the pure In2O3 thin film. Since the matrix of these two samples are both In2O3, and heat-treat in oxygen ambience at same temperature in the same time, We assume that the effect of the surface oxygen adsorption on the recombination lifetime (τr) is similar to the In2O3 thin film heat-treated at 800 oC and the Ag particles/In2O3 composite structure. Then, we discuss that if the optical generation rate (ge) cound be enhanced by Ag particles.
Hot electron effect of Ag particles can transferring the accumulated energy from incident light to electrons by non-radiative decay, and this process would produce highly energetic electrons, which may have sufficient energy to transport to the conduction band of In2O3 and provide excess carriers for In2O3. Therefore, the photo energy is not necessary higher than the band-gap energy of In2O3, and this was checked by illumination light with the photo energy lower that the band-gap energy of In2O3, the blue-light, green-light, and red-light. And, the photocurrent was also measured.
According to the results, photocurrent is observed that no matter the photo energy of incident light is higher or lower than the band-gap energy of In2O3. It can be proved that the hot-electron effect is applied on the Ag particles/In2O3 Ohmic contact structure, which would cause photo-excited electrons of Ag particles transferr to the conduction band of In2O3, and the excess carrier can be measured as photocurrent.
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Wang, Sheng-Hung, and 王盛弘. "Preparation of Ag/AgBr/TiO2/MWCNT Composite Photocatalyst in Visible Light Photocatalytic Application." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/87803894348628617777.
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博士<br>國立中興大學<br>化學工程學系所<br>102<br>Abstract
Titanium oxide (TiO2) is the most popular photocatalyst. However, the TiO2 application is restricted in the ultraviolet light (UV) irradiation. Thus, researchers are dedicated to improve the photocatalytic activity of TiO2 for the visible light application.
The purpose isof this study to synthsize the visible light responsive photocatalyst, and has been classified into three parts. In the first part, TiO2 thin films were prepared by the sol-gel method employing polyethylene glycol 1000 (PEG 1000) as an organic template. Pore sizes were adjusted by varying the concentration of PEG 1000. The optimal PEG concentration range required to form TiO2 films with a regular porous structure was investigated and was found to be 0.01–0.015 M. The results showed that the photocatalytic activity was correlated to the porous size and porous density. The TiO2 thin films possessing pore sizes in the diameter range of 35–85 nm exhibited the best conversion of 98% after 8 h of UV irradiation
In the second part, TiO2 particles are well coated on the multi-wall carbon nanotubes (MWCNT) by the directhydrolysis method. The results have been demonstratedthat MWCNT can enhance the photocatalytic activity by reducing the recombination of electron-hole pairs. The degradation of methyl orange can reach 80.0% under the UV light irradiation for 1h. There is no degradation under the visible light irradiation.
In the third part, silver bromide is added into the composite catalyst of TiO2/MWCNT by the precipitation method. The synthesized catalyst of Ag/AgBr/TiO2/MWCNT reveals the good responsive ability to visble light. The optimal synthesized parameters of catalyst in the process have been determined. The optinal amount of MWCNT is 1 wt%, and the suitable molar ratio of Ag/Ti is 10%, and the best calcined temperature is 400oC. The degradation of methyl orange can reach 82.3% under the visible light irradiation for 1h
In the forth part, the catalysts of Ag/AgBr/TiO2composite catalysts treating at hightemperature of 500oC, causing the catalysts have a smaller surface area. In order to increase the surface area, the suitable type of dispersant, the concentration of dispersnt, and the optimal synthesized pH value are determined. The Ag/AgBr/TiO2 synthesized in the pH11 solution with 0.1 M of cetyl trimethylammonium bromide (CTAB) has the best photocatalytic activity. The degradation of methyl orange can reach 89.0% under the visible light irradiation for 1h.
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Huang, Jheng-Long, and 黃正隆. "Plasmonics and Photocatalysis of Sputtered Ag Nanoparticles Impregnated in N-TiO2 Thin Films." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7wa4g7.
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碩士<br>國立東華大學<br>材料科學與工程學系<br>106<br>In this study, reactive magnetron sputtering was used to prepare different nitrogen doped titanium dioxide film (N-TiO2), which was combined with silicon dioxide layers and Ag nanoparticles (Ag NPs) to form a sandwich multilayer structure. The surface plasmon effect of Ag NPs could enhance the absorption of visible light of the film, and might improve the photocatalytic properties of titanium dioxide. The structure and crystallinity of the films were analyzed by XRD. The elemental composition and bonding of the films were examined by XPS. UV-vis spectrotometer was used to study the absorption phenomena of the films. The photocatalytic efficiency properties of the films under visible-light illumination were evaluated by measuring the decomposition rate of methylene blue in aqueous solution.
From the experimental results, with the increase of silver sputtering time, the content and the size of silver nanoparticles increased which resulted in enhancement of visible light absorption of the films, but the rate of increase is limited. The silver nanoparticles may combine with the oxygen in the air or with the oxygen of TiO2 films and get oxidized, which reduce the surface plasmon effect of the nano-silver and as a result decrease the visible light absorption of the film. For this reason, SiO2 layers were deposited above and below silver layer to protect from oxidizing. At 30 seconds (Ag30-NT) deposition time of Ag, the distribution of Ag nano-particle size is uniform, so we used this parameter to deposit N-TiO2/SiO2/Ag/SiO2/N-TiO2 multilayer. This structure can provide Ag NPs with good surface plasmon effect and enhance the absorbance of the films in the visible light. However, the film didn’t show significant photocatalytic property. The possible reason is that SiO2 layer is too thick, which makes electron and hole pairs of the film hard to reach the surface of the film and could not exhibit significant photocatalytic property. When the nitrogen flow rate is 20 sccm, N-TiO2 has 16.9 at% of nitrogen content. The phases of the film obtained were anatase, Ti3O5 and TiN. The absorption in the visible light of 20 sccm nitrogen doped with TiO2 (N20T) is 3-4 times higher than TiO2 film. In addition, depositing anatase TiO2 on sample N20T, improved the photocatalytic phenomenon about 80% compared to that of pure TiO2 films. So the catalytic properties of photocatalyst films were affected by the absorbance and surface properties of the films.
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Chang, Ching-hsing, and 張景星. "Enhanced Conversion Efficiency of Dye-sensitized Solar Cell by Utilizing Ag/TiO2 Composite Nanostructures." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/11744059919048782925.
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碩士<br>國立中央大學<br>材料科學與工程研究所<br>100<br>In this study, the Ag/TiO2 composite nanostructures were utilized as the photoanode in dye-sensitized solar cells (DSSC). For the reference cell, the titanium dioxide nanoparticles (TiNPs) was coated onto the FTO substrate by spin coating technique. The Ag/TiO2 composite nanostructures were applied to enhance the conversion efficiency of the DSSC. The material characteristics were analyzed by SEM, XRD, TEM, XPS, vmicro-Raman and UV-Vis measurements. The cells were then assembled an their I-V characteristics and incident photo conversion efficiency (IPCE) were measured by using the sunlight simulator measurement system.
The nanocomposite structures were implemented into DSSC in three ways. The first way is to introduce titanium dioxide nanotubes (TiNTs) into the DSSC. The results show that the efficiency was increased from 2.58% to 2.80% by increasing the photoanode thickness. It allows the dyes to be highly adsorbed, thus enhancing the conversion efficiency. The second way is to deposit silver particles acting as surface plasmons in DSSC. The cell efficiency was found to improve significantly as compared to the reference cell. The third way is by soaking the TiNT in saturated barium nitrate solution, modifying the TiNT surface by forming barium titanate. The efficiency was further enhanced. It was speculated that the dyes was highly adsorbed due to the higher isoelectric point of barium titanate. The integration of the DSSC with the BaTiO3/Ag/TiNT/TiNP and BaTiO3/TiNT/Ag/TiNP structures increased the solar cell efficiency up to 3.31% and 3.07%, respectively.
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Chang, Che-Cheng, and 張哲誠. "Characterization of TaOxNy-Ag composite thin films prepared by reactive magnetron sputtering." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/21342765666339117077.
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碩士<br>明志科技大學<br>化工與材料工程研究所<br>97<br>TaOxNy and TaON-Ag composite films were deposited by reactive co-sputtering on Si and quartz glass substrates. The films were then annealed using RTA (Rapid Thermal Annealing) from 500℃~800℃ for 5 minutes respectively to induce the microstructural, optical properties, photodegradation and anti-bacterial properties of these films was studied. For the investigation of TaOxNy and TaON-Ag films, the films were examined using XRD(X-Ray Diffraction),UV-VIS-NIR(ultraviolet-visible-spectrophotometry),FESEM (Field Emission Scanning Electron Microscopy),TEM (Transmission Electron Microscope), and C-AFM (Conductive Atomic Force Microscopy). The results reveal that when the (O2+ N2)/Ar ratio is around 9.1% and after being annealed at 800 oC, the TaON film become crystallized. When Ag was doped into the films, it was found that the crystallization may be induced at low temperature and the optical band gap may decrease. The emergence of Ag nano-particles on TaON film surface is critical to the film’s antibacterial behavior. The sample deposited at 300 oC is able to produce outstanding antibacterial behavior with or without visible light illumination. At its best, the TaON-Ag's antibacterial efficiency can reach greater than 99 %. The synergistic effect combining the dissolution of Ag and the photocatalytic characterisics of TaON is thought to be the reason for the enhancement of antibacterial behavior. By examining the photodegradation of methylene blue, it is further confirmed that Ag doping in TaON can enhance the photocatalytic behavior of the composite films.
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Lai, Chin-Chuah, and 賴欽詮. "The Study of Extrinsic-Doped TiO2 Bulks, Thin Films and Composite Capacitors." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/01232471888905250197.
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碩士<br>國立東華大學<br>材料科學與工程學系<br>90<br>The development of future ultra-large scale integration (ULSI) storage capacitors and dynamic random access memory (DRAM) requires new dielectric materials. There is a significant interesting in using TiO2 for the fabrication of charge storage insulators in the next generation memories and gate oxide material for replacing SiO2 for deep submircon scaling of ULSI devices.
In this research, different doping materials (Nb2O5, MgO, ZrO2, and co-doping of Nb2O5 and MgO) were added to TiO2 ceramic powder to study the effect of extrinsic (donor- or acceptor-doped) and intrinsic dopants on the properties of TiO2. The doped powder was used to fabricate bulks, composite capacitors, and thin films. The effect of annealing temperature on dielectric properties and resistivity was investigated for doped TiO2 bulks after vacuum sintering. Composite capacitors were fabricated by using doped TiO2 as the second phase and the epoxy as the matrix. Thin films of multi-doped TiO2 were deposited on bare Si (100) and electroded Si (Pt/Ti/SiO2/Si) by R.F. magnetron sputtering by using hot pressed doped-TiO2 ceramic targets. The research of doped-TiO2 thin films was focused on the evaluation of their growth kinetics, microstructure, mechanical properties, electric properties, and optical properties.
The results showed the bulks were dense except for the TiO2 with 20 vol% ZrO2. The addition of Nb2O5 to the bulk resulted in higher dielectric constants and loss tangents. The MgO- and ZrO2-doped bulks which were annealed at 800℃ after vacuum sintering possessed a extremely high dielectric constant, but accompanied by a higher loss tangent. The bulks with co-doped Nb2O5 and MgO had slightly lower dielectric constants, as compared with these of Nb2O5-doped bulks, and much lower loss tangents.
For composite capacitors, the dielectric constants of 10~30 were obtained. The value is slightly lower than those obtained previously in our laboratory.
For thin films, the XRD results showed thin films were easier to crystallize at a shorter working distance between target and substrate. Extrinsic doping caused porosity in thin films. Growth rate decreased with increasing oxygen partial pressure and working distance. Regarding to mechanical properties, residual stress was compressive for all thin films. The dielectric constant and loss tangent increased with the amount of Nb2O5-doped films, but decreased at higher oxygen partial pressure. The addition of MgO decreased dielectric constant and loss tangent except for the 10 vol% MgO-doped TiO2 films. With the 4 vol% ZrO2 dopants, TiO2 films possessed a lower dielectric constant and loss tangent. Resistivity and breakdown field of thin films were influenced by doping, fabrication, and heat treatment. The maximum values of resistivity and breakdown field were approximately 1013 Ω-cm and 4 MV/cm, respectively. Refractive indices of thin films were in the range of 2~3.
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Tsai, Ming-Jong, and 蔡明忠. "The Study of Composite and Multilayered (Ta2O5)-(TiO2) High Dielectric Thin Films." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/14721180840180881616.
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碩士<br>國立雲林科技大學<br>電子工程與資訊工程技術研究所<br>88<br>The development of future generation of DRAM will require the introduction of new materials with high dielectric constant. In this thesis, thin dielectric films composed of either a composite or alternating layers of tantalum pentoxide and titanium dioxide were deposited by radio-frequency (RF) magnetron sputtering. The material and electric properties of the deposited (Ta2O5)-(TiO2) high dielectric thin films were investigated.
This paper reports on highly reliable stacked storage capacitor with high capacitance using RF Sputtering to deposit Ta2O5-TiO2 composite and Multilayer films. Post-deposited thermal treatments were applied to (Ta2O5)1-X-(TiO2)X composite films. Al/(Ta2O5)-(TiO2)/Pt/Ti/SiO2/Si (MIM) structure was fabricated to measure the electrical and physical properties. Ta2O5-TiO2 composite and multilayer films were investigated from the viewpoint of leakage current density, dielectric constant. According to the C-V and I-V measurements, the dielectric constant was estimate to be 63 and leaky density was observed to be 2.9*10-8 A/cm2 at the electric flied of 0.5 MV/cm for the 70-nm-thick (TiO2)0.08-(Ta2O5)0.92 composite films annealed at O2 700oC 1min. The dielectric constant was estimate to be 38 and leaky density was observed to be 3.4x10-7A/cm2 at the electric flied of 0.5 MV/cm for the 60-nm-thick (Ta2O5)/(TiO2)/(Ta2O5) (20nm/20nm/20nm) multilayer films.
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ng, yeow-leong, and 黃耀龍. "Study of Ag loading on TiO2 incorporated with montmorillonite composite powder by thermal hydrolysis technique." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/36469331929524978050.
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碩士<br>國立東華大學<br>材料科學與工程學系<br>93<br>Since the easily aggregation of the TiO2 nano-particles will reduce its reaction surface area, montmorillonite becomes an ideal medium by its good adsorptions ability and great cation exchange capacity (CEC). Thermal hydrolysis technique was used for TiO2 formed, nucleated and grown in the interlayer space of pillared montmorillonite so that the nano-particles can effectively disperse in order to increase the reaction surface area and photocatalysis efficiency.
According to the previous study, we found that choosing 0.1M titanium tetrachloride and the heating temperature at 70℃ exhibited the best photocatalytic efficiency, and the major phase of titanium dioxide particles was anatase. Based on these conditions, furthermore subjects had been studied such as quantity of silver loading, ways of powder purification and drying methods that would influenced on photocatalytic efficiency of the composite powders.
The UV absorption spectrum of the composite powders showed no shifted after loading Ag or Cu, means that metal particles of loading only play role of trapping electron so that to decrease the recombination efficiency of electron/hole. In the results of methylene blue degradation experiment, 2mol% of Ag and 2mole% of Cu loading had the best photocatalytic efficiency.
Thermal hydrolysis technique would released large amount of ionic impurities like H+ and Cl-. Purification by ammonia solution and then calcined to 450℃ would completely remove ionic impurities, but photocatalytic efficiency exhibited much lower than purification by great quantity of water. Even though purification by water had showed better performance on photocatalytic efficiency, ionic impurities still remained such as Cl- so that AgCl had formed when Ag loading process had been proceeded. AgCl would not enhanced photocatalytic efficiency.
For pillared layers structure of montmorillonite, during normal air drying, the liquid-vapor interfacial tension is so strong that silicate layers
verlapping and kept apart only by metal pillars, resulting in regular structure. In case of freeze drying, the interfacial tension could be reduced greatly and the silicate layers and pillars would kept their wet-cake structure, meaning more macropores and no more regu;ar layered structure, exhibited higher photocatalytic activity than other drying method.
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CHANG, CHIA-JUI, and 張嘉叡. "Preparation of Ag/TiO2 Composite Nanofibers by Electrospinning Application for Photoelectrochemical Degradation of Azo Dyes." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/2sh454.
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碩士<br>弘光科技大學<br>職業安全與防災研究所<br>107<br>Azo dyes has been widely utilized in dyeing and finishing plant. The cause of the production of azo dyes are environmental pollution and potential carcinogenicity to human health by the production of azo dyes. Therefore, this study used Orange II as the target pollutant.
The research was divided into two parts: First, the preparation of Ag/TiO2 composite nanofibers electrode by electrospinning is discussed, and using if to analyze the composite nanofibers electrode by FE-SEM、XRD、TGA and 3D Raman. The optimum electrospinning were PVP concentration, injection rate, voltage, collection distance, and calcination temperature are found to be 0.05 g/mL, 0.03 mL/min, 15 kV, 10 cm, and 450 °C, respectively.
The second part is degradation of azo dye by photoelectrochemical Fenton process with anode Ag/TiO2 after 30 minutes of experimentation combined with cathode carbon fiber cloth, the optimum voltage strength, Electrolyte concentration, oxidizing agent concentration, oxygen flow rate, temperature, and pH value are found to be 30V, 5 mM, 0.5 mM, 300 cm3min-1, 298 K, and pH 3, respectively. The azo dye removal efficiency can reach 92.8% under the optimum operating conditions. However, compared with previous literature, Ag/TiO2 as anode electrode can effectively improve electrical conductivity and removal efficiency by 20% ; According to the reaction kinetics analysis, this study is the pseudo-second order kinetic with a correlation coefficient(R2) of 0.9839 and reaction rate constant of 0.045 mg L-1 min-1.
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Huang, Tzn-Yun, and 黃子芸. "Microstructures and magnetic properties of CoPt-ZnOx/ Ag composite magnetic recording thin films." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/17777720263620946740.
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碩士<br>臺灣大學<br>材料科學與工程學研究所<br>98<br>In this study, the CoPt, CoPt/ Ag, CoPt/ ZnOx, (CoPt/ ZnOx)n, (CoPt)y-(ZnOx)1-y, and (CoPt)y-(ZnOx)1-y/ Ag films were deposited on glass substrates at room temperature by dc magnetron sputtering. The effects of Ag underlayer, ZnOx underlayer, ZnOx addition, and process parameters on the microstructure, magnetic properties, and magnetic easy axis of the film were investigated.
The ordering temperature of CoPt films could be reduced from 600~700℃ to 500~600℃ as Ag underlayer was introduced. The introduction of Ag underlayer could promote the out-of-plane magnetic properties of CoPt films.The out-of-plane coercivity, in-plane coercivity, out-of-plane squareness and in-plane squareness values of Co56.42Pt43.58 (20 nm)/ Ag (30 nm) film which annealed at 700℃ for 30 minutes are 17.6 kOe, 15.4 kOe, 0.85 and 0.51, respectively.
The CoPt/ ZnOx multilayer with ZnOx sputtering power density, 2.81 watt/ cm2, showed out-of-plane magnetic anisotropy after annealing at 700℃ for 30 minutes, and (CoPt/ ZnOx)3 multilayer also presented the out-of-plane magnetic anisotropy after annealing at 700℃ for 30 minutes.
The ZnO target and the CoPt target were co-sputtered to form the granular CoPt films. The high ordering of (CoPt)75-(ZnOx)25 film could be obtained after annealing at 700℃ for 30 min. It suggests that ZnOx additives would leave vacancies and defects after annealing, which provides the diffusion path of Co and Pt atoms and improves the ordering of CoPt films.
Finally, the 30 nm-Ag layer was introduced under the (CoPt)y-(ZnOx)1-y film and then annealed at 700℃ for 30 min. The larger out-of-plane coercivity of (CoPt)95-(ZnOx)5/ Ag film could be obtained because of the decrease of the exchange coupling. Besides, the ZnOx would precipitate at the grain boundaries of CoPt and Ag layers as the content of ZnOx additive increased to 50 vol%, which could isolate the CoPt and Ag grains and inhibit the grain growth of CoPt. ZnOx would reduce the epitaxial effect between CoPt and Ag layers and lead (CoPt)50-(ZnOx)50/ Ag film to the random orientation.
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Chen, Yu-Yan, and 陳毓讌. "The analysis materials of TiO2-SiO2 Composite Films on the 304 Stainless Steel." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/04640111445144289607.
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碩士<br>國立高雄應用科技大學<br>機械與精密工程研究所<br>99<br>The 304 austenitic stainless steel in particular austenitic grade are often used in chemical and food industries because of its excellent corrosion resistance.In this study, DC plasma nitriding in order to overcome the arc caused by injury and effect of point. Using the active screen technology for plasma nitridation surface engineering to make use of a uniform cavity temperature,fewer arc caused by injury and effect of point.
The experimental results show that pass into the Ar / O / N in the case of plasma produced by the sample surface contribute to refining the grain size. Cr and Ni increase, helping to maintain a good resistance to corrosion damage and the plasticity and toughness. The modified surface morphology that pass into the Ar / O / N in the case of plasma produced with the increase in processing time, which leads to oxidation of substances with oxygen in the plasma, produce Volatile products produced with the substrate, such as CO, CO2 , etc. thus improving the surface hydrophilicity, can improve the hydrophilic nature of the surface, but also sample a relatively flat surface morphology. XRD analysis of the coating material is a mixture of TiO2-SiO2, Which was found by the modified structure of TiO2, but the structure of SiO2 is almost not observed. The Ar / O / N plasma treatment, 240min after the coating hardness than the untreated specimens coated specimen directly above 0.1Gpa. that pass into the Ar / N in the case of plasma produced , the processing time is too long, but the surface holes caused by cracks in the specimen. The Ar / O / N plasma treatment, 240min after the coating hardness than the untreated specimens coated specimen directly above 0.1GPa, and by the Ar / N 180min after plasma treatment the hardness of coated specimens Slightly higher than plasma specimens without the higher 0.0421GPa.
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SU, YU-TAI, and 蘇祐台. "Enhanced Photothermal Phenomena of SiO2-Ag and TiO2-Ag Multilayered Thin Films and Their Comparison with Pulse Current Heating for TaN-(Ag,Cu) Thin Film Annealing." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/82765653311566866456.
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碩士<br>明志科技大學<br>材料工程系碩士班<br>102<br>The first part of this study. Multi-layered thin films of SiO2/Ag and TiO2/Ag were prepared on glass substrates using reactive sputtering, followed by rapid thermal annealing. The mass thickness of Ag was controlled at 3~10 nm. The optical properties of these films were then studied as functions of Ag layer-thickness, annealing time, and matrix materials. It was found that the heating enhancement due to the incorporation of Ag particles is significant, especially when TiO2 was used as the matrix. Embedded Ag particles led to an increase in light absorption in the range of UV to IR region (400 nm to 2400 nm). As a result, the films’ temperature can increase dramatically, caused by the irradiation of light. The largest temperature increment could reach >100 oC easily. The increments were dependent on the number of Ag layer, heat treatment conditions, light intensity, and the oxide matrix. A theory was proposed to explain the enhanced light absorption and, therefore, the enhanced heating effect due to light irradiation. At final, an example was given to explain the possible annealing of TaN-(Ag,Cu) thin films by using the enhanced photothermal effect. The Second part of this study we annealed the TaN-(Ag,Cu) thin films by pulse current heating. The property of pulse current heating has been measured.By controlling the parameterswe of pulse current including on/off rate and heating time we bserved that the difference of temperature between the surface (TaN-(Ag,Cu)) thin films and substrates (PI) was up to 110 oC. In this study we successfully annealing the TaN-(Ag,Cu) thin films by two kinds of heating process and the Surface morphology,Antibacterial efficiency were tested.
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Su, Chia-Yi, and 蘇家怡. "A Study on Electrostatic Discharge Protection of Additional MWCNT /Ag on Polyurethane Composite Films." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/8hx34a.
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碩士<br>國立臺北科技大學<br>化學工程研究所<br>98<br>Stage one of this study, pre-polymer of polyurethane was synthesized with a prepolymer mixing process, by adding polyol M6220, poly propylene glycol and isophorone iisocyanate. In addition this product is neutralized by triethyl amine, and then reacted with 1,4-butanediol as chain extension agent. Finally anionic aqueous polyurethane was synthesized by adding deionized water to the above product. During the reaction process, we used fourier transform infrared spectrophotometer in order to measure the changes of NCO group to determine the reaction was completed. Stage two, we used MWCNT with 10-20 nm in diameter, 0.1-10μm in length, and 95% of purity. These were treated by a concentrated H2SO4 and HNO3, and then ultrasonicat ed with AgNO3, PVP, SDS and NaOH in ethylene glycol solution for nanosized Ag particles deposition on it. Finally we prepared conductive composite film by mixing1%, 5%, 10%, 15% of MWCNT/Ag and carbon black EC-600JD with aqueous polyurethane, and investigated the effects of different content percentage on electrical conductivity, thermal stability and antibacterial effects. The microstructure and surface morphology of Ag/MMWNT composite was investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and fourier transform infrared spectrophotometer. The electrical conductivity and thermal stability of polyurethane composite films was measured by resistance meter and thermogravimetric analysis. Degradation temperatures is enhancing 17 oC than aqueous polyurethane by adding 10% of MWCNT/Ag, and conductivity is increased from 6.12×10-5 to 3×10-4 by adding 5% of CB and MWCNT/Ag. For antibacterial, we can reach antibacterial effects by adding 1% of MWCNT/Ag.
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HE, JHAO-YI, and 何昭儀. "The Preparation and the Properties of Ag Nanoparticles/Sodium Alginate/Polyvinyl Alcohol Composite Films." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/49989404196072435217.
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碩士<br>逢甲大學<br>纖維與複合材料學系<br>102<br>This study is divided into three parts. The first part is the preparation of sodium alginate /polyvinyl alcohol composite films. After the solution with 3 wt% sodium alginate and 15 wt% polyvinyl alcohol was mixed. The FT-IR and VVSEM show there are only hydrogen bond and a good compatibility. The mechanical properties showed SAP82 have the best strength at break 46.8 MPa and it increase 324%. From TGA, the decomposition temperature of films increased from 248.46 ℃to 265.22 ℃with increasing PVA content.
The second part is the preparation of the nano silver /sodium alginate film. We use of 3 wt% sodium alginate as a protective agent, silver nitrate as silver nanoparticles reduction by using oxidation-reduction methods in the sodium alginate solution, then obtained the nano silver/ sodium alginate films. By UV-vis, EDS, TEM, SPSA, VVSEM analysis confirmed the presence of nano-silver having an average particle size of all less than 100 nm, The mechanical properties and antibacterial analysis showed Ag1000SA have the best strength at break 80.37 MPa and it increase 180%, and have a degree of antibacterial effect. The rheological analysis results display that with increasing shear rate and temperature, the apparent viscosity of the solution fall. And with nano-Ag content had increased Non-Newton index will decrease first and then increased.
The third part is the preparation of the best ratio of nano silver in second part / sodium alginate / polyvinyl alcohol composite film. By adding polyvinyl alcohol, investigate the effect of different amounts of nano silver / sodium alginate / polyvinyl alcohol films. From UV-vis, VVSEM contain silver nanoparticles and particle size are smaller than 100 nm, remained nanoscale. The mechanical properties showed the strength at break of samples containing the best ratio of the silver nanoparticles are better than non-contained samples. With the increase in the proportion of polyvinyl alcohol, to improve the elongation at break 657%.
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Jheng, Chian-fang, and 鄭千芳. "The study on preparation and the characterization of nano-composite Ag/TiO2 photocalayst by sol-gel method." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/52487026428069564089.
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碩士<br>國立雲林科技大學<br>工業化學與災害防治研究所<br>93<br>In this study, nano-composite Ag/TiO2 phototcatalyst has been prepared by sol-gel method with addition of silver. The effect of different Ag/TiO2 molar ratios and annealed temperature on the properties of nano-composite photocatalyst material has been discussed. The samples were characterized by various analytical techniques, such as Thermogravimetric Analysis(TGA), UV-Visible Diffuse Reflectance Spectroscopy(UV-Visible), X-Ray Diffraction(XRD), low temperature N2 adsorption(BET), Transmission Electron Microscope(TEM) and Scanning Electron Microscope(SEM). The photocatalytic activity of the prepared sample was evaluated by photolysis solid–liquid phase of methylene blue and the solid-gas phase of aldehyde and anti-bacterial activity.
The result of TGA reveals that the steady state temperature is 500℃ for titania, but the nano-composite Ag/TiO2 improves the steady state temperature up to 600℃. The result of XRD reveals that nano-composite Ag/TiO2 shows a significance of phase transition from anatase to rutile in comparison with pure titania. The temperature change for phase transition from 600℃(TiO2) to 700℃(Ag/TiO2) indicates that silver loading is capable of inhibiting phase transition. Moreover, the result of UV visible analysis shows that the addition of silver cause no change on the band gap energy of TiO2. From TEM and SEM micrographs, the grain size of TiO2 at 500℃ is approximately 15~20nm. however, the grain size of Ag/TiO2 at the same temperature is approximately 10~15nm. Therefore, it is understood that silver loading inhibits the growth of TiO2 crystal size. The specific surface area of 44.714m2/g for TiO2 was determined from the BET analysis, the result reveals that an applicable amount of silver loading will increase specific surface area, but in excess it will decrease specific surface area. Thus 2%Ag/TiO2 is preferred which gives the best specific surface areas of 63.24m2/g.
The solid-liquid phase photocatalytic reaction of nano-composite 2%Ag/TiO2 photocatalyst under UV light exposure for 420 min demonstrated nearly 90% degradation of methyl blue. Under a similar condition the solid-gas phase photocatalytic reaction of nano-composite 2%Ag/TiO2 photocatalyst was exposed for 240 min and demonstrated nearly 92% degradation of acetaldehyde. On anti-bacterial test it was found that 2%Ag/TiO2 nano-composite material have good anti-bacterial properties. From all of the test results, it is clear that the silver loading TiO2 is able to increase the photocatalytic activity and have good anti-bacterial properties.
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Lin, Ya-Han, and 林亞翰. "Study on the Preparation and Application of Composite Ag/TiO2 Photocatalyst by Pulsed Discharge Plasma in Water." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/vwj23y.
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碩士<br>國立雲林科技大學<br>化學工程與材料工程系<br>103<br>The composite Ag/TiO2 photocatalyst powder was prepared by liquid pulsed plasma discharge. Titanium rods were used as conductive electrodes in the reaction tank containing titanium flakes, silver flakes and ultra pure water. The synthesis of the composite Ag/TiO2 photocatalyst powder was performed by varying the pulsed discharge duty cycle pulse period and the electrode discharge point. The chemical composition, particle size and microstructure of the composite Ag/TiO2 photocatalyst powder were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), dynamic light scattering (DLS), and Raman spectroscopy. Results indicated that enhanced yielding and particle size of the composite Ag/TiO2 photocatalyst powder were obtained when increasing θ, τ,V,P and silver content. Desired submicron particle size and crystallinity of the composite Ag/TiO2 photocatalyst powder can be prepared by a controlled approach utilizing the liquid pulsed discharge plasma.
The composite Ag/TiO2 photocatalyst powder was then sintered at 450, 500 and 550oC at the heating rate of 10 oC/min. The composite Ag/TiO2 photocatalystv powder demonstrated good anatase crystallinity at 450 oC. The average particle size of the produced 1wt%, 3wt%, 5wt% and 8wt% composite Ag/TiO2-450 oC photocatalyst powder were 40.66 nm, 41.59 nm, 41.68 nm and 41.65 nm, respectively. In addition, uv-visible diffuse reflectance spectroscopy analysis showed that 8wt% Ag/TiO2 photocatalyst powder has the highest absorbance with an energy gap value of 3.0 eV, and a red shift phenomenon.
The composite Ag/TiO2 photocatalyst powder was prepared by the liquid phase plasma method. The 8wt% Ag/TiO2 photocatalyst powder after 2- and 12-hour UV irradiation has 94% and 86% effective photo-decomposition of methylene blue dye and methyl orange dye, respectively.
Antibacterial tests against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were assessed. The 3 wt % Ag/TiO2 photocatalyst powder has a bactericidal effect of over 99.99% for S. aureus with a minimum bactericidal concentration (MBC) of 0.059 ppm. With 1 wt % Ag/TiO2 photocatalyst powder, similar effect for E. coli can be achieved with a MBC of 0.003 ppm.
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Tsai, Ming-Shiann, and 蔡明憲. "Research of Deposited High Quality (TiO2)-(Ta2O5) Composite Dielectric Thin Films by RF Sputter." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/11281315648444871017.
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碩士<br>國立雲林科技大學<br>電子與資訊工程研究所碩士班<br>90<br>(Ta2O5)0.92-(TiO2)0.08 thin films with a thickness of 60 nm were deposited on p-Si (100) substrate by RF sputtering method. The temperature of the substrate are set from 25°C to 300°C during deposition.
In this issue, the dielectric constant is depend on growth temperature. The effective dielectric constant of deposited film grown at 250°C is obtained about 24 and the leakage current density(1.65×10-8A/cm2 at 1.5V) decreases two orders when compared with as-deposited samples(1.42×10-7A/cm2 at 1.5V). Pre-O2 plasma treatment is applied on (Ta2O5)0.92-(TiO2)0.08 thin film that will improve effective dielectric constant(εr=16) and leakage current density(2.30×10-8A/cm2 at 1.5V).
To compare among these O2 plasma annealed samples, the highest dielectric constant(εr=20) is measure from that annealed with O2 plasma for 15 minutes, and the lowest leakage current density(1.47×10-8A/cm2 at 1.5V) is obtained from that for 10 minutes. Among the furnace annealing samples, the dielectric constant of 750 °C annealed 15 minutes is the highest(εr=18) and the lowest leakage current density is annealed 10 minutes(3.42×10-9A/cm2 at 1.5V). The dominant leakage mechanisms are the Schottky Emission at low electric field and the Poole-Frenkel at high electric field.
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Hu, I.-Ling, and 胡怡玲. "Studies on the properties and characterization of the conducting polyaniline/ nano-TiO2 composite films." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/at58c7.
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碩士<br>國立臺北科技大學<br>化學工程所<br>93<br>The dissertation describes the studies of the composite films which is composed of the particles of polyaniline (PANI) characterized by conducting polymer, nano-TiO2 as semiconductor nanoparticle, and dimethyl sulfoxide (DMSO), and milled. The properties of these composite films are different from those prepared from electrochemical polymerization.
Physical properties for PANI / nano-TiO2 is assayed via particle size analysis, cycle voltammetry, four-point probe, FTIR and SEM. Different redox potentials show in cycle voltammetry when composites by different percentage particles of nano-TiO2 incorporated into PANI, coated on Pt electrode and dehydrated naturally, and finally put it in acid solution of oxidizing agents.
The results illustrate that the best related physical properties for composite films are made of PANI / nano-TiO2 (46wt.%). In cycle voltammetry, two pairs of redox potentials are available. Besides, adsorbance peaks for PANI/ nano-TiO2 in IR spectrum obviously exhibit red-shift due to DMSO added. Furthermore, the electrical conductivity of composites PANI / nano-TiO2 is estimated to be 0.3∼16 mS/cm by measurements with four-point probe.
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Huang, Sheng-jie, and 黃聖絜. "A Study on Fabrication and Functional Properties of Polyurethane/ Nano Ag@ Coir Charcoal Composite Films." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/87959203190645863252.
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Tsai, Sung-ping, and 蔡松? "The study on prepartion and characterization of nano-composite Ag-SiO2-TiO2-MWNT photocatalytic by sol-gel method." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/44778171630294735599.
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碩士<br>國立雲林科技大學<br>化學工程與材料工程研究所<br>99<br>In this study, nano-composite Ag-SiO2-TiO2-MWCNT phototcatalyst has been prepared by sol-gel method with addition of silver. The effect of different Ag-SiO2-TiO2-MWNT molar ratios and annealed temperature on the properties of nano-composite photocatalyst material has been discussed. The samples were characterized by various analytical techniques, such as Thermogravimetric Analysis(TGA), UV-Visible Diffuse Reflectance Spectroscopy(DRS), X-Ray Diffraction(XRD), low temperature N2 adsorption(BET), Transmission Electron Microscope(TEM) and Scanning Electron Microscope(SEM). The photocatalytic activity of the prepared sample was evaluated by photolysis solid–liquid phase of methylene blue and anti-bacterial properties.
The result of Thermo-gravimetric Analysis (TGA) , after 270℃ it shows the addition of SiO2 leads the stabilization to Thermo-gravimetric weight loss , and the result of XRD and UV-Visible Diffuse Reflectance Spectroscopy(UV-Visible) are reveal that 4mol% addition of Ag+ and calcination at 500℃ in N2 surrounding were the best condition.
The solid- liquid phase photocatalytic reaction of degradation of methyl blue by using :
(1) nano-composite 4%Ag-SiO2-TiO2-MWNT
(2) nano-composite 4%Ag-SiO2-TiO2-MWNT with surface treatment by H2O2
(3) nano-composite 4%Ag-SiO2-TiO2-MWNT with surface treatment by H2O2 and UV light irradiation
the nano-composite 4%Ag-SiO2-TiO2-MWNT with surface treatment by H2O2 photocatalyst under UV light exposure for 60min demonstrated up to 96.2%.
nano-composite were dip-coating on PET to degration of methylene blue, it’s degration rate up to 90%,and after 10 times washes it remain the efficiency up to 80%.
In the anti-bacterial property test the result shows that 4%Ag-SiO2-TiO2-MWNT has well efficiency in anti-bacterial, under UV light irradiation in 60 min has been no bacteria exist, and without UV light irradiation support the composite photocatalyst has been no bacteria in 90 min, but under UV light without photocatalyst it shows no decrease of bacteria.
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Tang, Chien-Jen, and 唐謙仁. "Analysis of Ta2O5-TiO2 and Ta2O5-SiO2 composite films prepared by ion-beam sputtering deposition." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/92515946297856820855.
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博士<br>國立中央大學<br>光電科學研究所<br>95<br>There are two important topics on optical coatings. First, we have to develop thin film materials with good optical properties, mechanical properties, and environmental stability. Second, we need to develop new methods to design optical multilayer coatings. The development of the new materials is helpful to study these two topics. Mixing two thin film materials is an interesting technology to develop new thin film materials.
In this article, the radio frequency ion-beam sputtering deposition (RF-IBSD) system was used to prepare composite films. An ion source was used to bombard two targets simultaneously. The composite proportions are determined by the area ratio of two targets and the area ratio could be adjusted by moving the targets with a step motor. In this experimental have two parts. First, to study the material of high refractive index composite film, Ta2O5-TiO2 composite films prepared by Ti and Ta targets. The refractive indices and extinction coefficients of the composite films were found to be between those of the TiO2 and Ta2O5 films. The structure of the as-deposited films was amorphous, and the surface roughness was about 0.1 nm. The residual stress of the composite films was less than that of pure TiO2 film. The structure of the composite films after annealing was amorphous, with low surface roughness and slightly increased residual stress. Second, to study the gradient-index composite films, Ta2O5-SiO2 composite films were prepared by Ta and SiO2 targets. Ta2O5-SiO2 composite films with refractive indices varied from 1.52 to 2.16, and low extinction coefficient was about 10-4@550nm. All the composite films were amorphous and had surface roughness less than 0.1 nm. The residual stress and substrate deflection of rugate filter would be smaller than that of the multilayer filter which was made by stacking up alternatively with high and low refractive index materials. To sum up, the composite films could be used for high quality optical coating materials and gradient-index optical coating.
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Antunes, José Miguel Lopes. "Fabrication of nanomaterial composite based liquid repellant facemasks." Master's thesis, 2021. http://hdl.handle.net/10316/97998.
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Dissertação de Mestrado Integrado em Engenharia Biomédica apresentada à Faculdade de Ciências e Tecnologia<br>Com o aparecimento da pandemia Covid-19, ficou ainda mais visível a necessidade da existência de superfícies antimicrobianas, especialmente em contextos hospitalares. Os têxteis médicos são das superfícies mais complicadas de modificar, uma vez que o seu uso típico envolve contacto direto com o corpo humano, e consequentemente, existem vários aspetos a serem melhorados, tais como o tempo de utilização, capacidade antibacteriana e antivírica ou hidrofobicidade. De maneira a melhorar a eficiência de máscaras faciais e outros têxteis médicos, vários estudos foram feitos, como a implementação de camadas filtradoras modificadas, com por exemplo nano fibras, ou como a modificação da superfície de filtros através da adição de materiais com capacidades hidrofóbicas de maneira a aumentar a sua eficiência. Está comprovado que adição de agentes antimicrobianos a estes produtos é uma maneira extremamente eficiente para prevenir infeções causadas por diversos patogénicos através da inibição de vírus, fungos e bactérias. Existem diferentes métodos químicos e físicos para promover alterações superficiais em tecidos. Apesar de os métodos mais utilizados são processos baseados em soluções, outros métodos têm chamado á atenção nos últimos anos, tais como os métodos de deposição física em fase de vapor. A tecnologia de deposição física em fase de vapor tem sido implementada para modificar a superfície de diversos materiais, com particular atenção aos têxteis. Nesta tese irão ser analisados como revestimentos de Diamond-like Carbon dopados com nanopartículas de prata podem ser uma abordagem eficiente para transformar têxteis normal neste utilizados em aplicações biomédicas, um revestimento que irá ser depositado através de um processo de pulverização catódica. O principal foco vai ser testar se é possível de dar propriedades antibacterianos e hidrofóbicas aos têxteis escolhidos.<br>The Covid-19 pandemic has, even more, highlighted the need for antimicrobial surfaces, especially those used in a healthcare environment. Medical textiles are one of the most difficult surfaces to modify since their typical use is in direct human body contact, and, consequently, some aspects need to be improved, such as wear time, antibacterial and anti-viral capacity, or hydrophobicity.To improve the efficiency of facial masks and other medical textiles, several studies have been performed, like employing modified filter layers, for instance, nanofibers, or by modifying the filter surfaces by adding materials with antimicrobial capabilities to improve their efficiency. It's proven that adding antimicrobial agents to these products is a highly effective way to prevent infections caused by various pathogens through the inhibition of viruses, fungi, and bacteria. There are different chemical and physical methods to promote superficial changes in fabrics. Although the most used ones are solution-based processing, other methods have been attracted a lot of attention in the last years, like physical vapor deposition methods. The PVD technology has been implemented to modify various material surfaces, with particular attention to textiles.In this thesis, it will be analysed how DLC doped with AgNPs coatings can be an efficient approach to transform textiles commonly used in biomedical applications, a coating that will be deposited by using a Magnetron Sputtering process. The main focus will be to test if it is possible to give antibacterial and hydrophobic properties to the chosen textiles.
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Chia-TaiHsu and 許家泰. "Study on characterization and electrical properties of SnO2 films and composite films (SnO2/nano-Ag/SnO2) by R.F. magnetron sputtering deposition." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/44045449120470845312.
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碩士<br>國立成功大學<br>地球科學系<br>104<br>SUMMARY
In this study, SnO2 film with different depositional parameters (depositional power, Ar:O2, and substrate temperature) and composite films (SnO2/nano-Ag/SnO2) are fabricated on (100) Si substrates by using radio frequency (r.f.) magnetron sputtering deposition. After preparation of the films, the as-deposited films are examined by using these equipment below: The crystal structure is analyzed by X-ray diffraction (XRD), morphology and thickness are observed by atomic force microscopy (AFM) and Field-Emission Scanning Electron Microscopy (FE-SEM), conductivity is measured by conductive atomic force microscopy (CAFM) and Van Der Pauw method, optical properties are UV-Vis and chemical X-ray Photoelectron Spectrometer (XPS).The opto–electronic properties of SnO2 films and composite films are related to its oxygen vacancy, thickness, crystallinity, and nano-Ag type (size and distributed). It can be concluded the opto–electronic properties of SnO2 films and composite films would be influenced by the deposition parameters. Last, we can conclude that if the samples were suitable to be a Transparent Conductive Oxide (TCO) by the figure of merit (FOM). And it’s obvious difference in each sample.
Keywords: SnO2 film, composite film, r.f. magnetron sputtering, conductivity, CAFM.
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Chang, Tian-Hsin, and 張天信. "Improvement in the Dielectric Properties of (Ta2O5)0.92-(TiO2)0.08 Composite Thin Films by Oxygen Plasma Treatment." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/19091538190294169689.
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碩士<br>國立雲林科技大學<br>電子與資訊工程研究所碩士班<br>89<br>The effect of oxygen plasma treatment on the properties of as-deposited 1000Å thick high-dielectric thin films has been investigated. Tantalum pentoxide and Titanium dioxide composite film (Ta2O5)0.92-(TiO2)0.08 was deposited on Pt/Ta/SiO2/Si substrate by RF sputtering method. There is no any intentional heating of the substrate took place during all kinds of deposition conditions. In this article, not only O2 plasma but the furnace annealing , two-step annealing and alternative sputter way were considered.
As deposited (Ta2O5)0.92-(TiO2)0.08 films were exposed under oxygen plasma with different duration . Compared to pure Ta2O5 (ε=25) thin film, significant enhancement in dielectric constant(ε=52) is obtained by 15 minutes of oxygen plasma duration. It was also found that the leakage current density, 3.2 ×10-9 A/cm2 at an applied voltage of 1.5 V, of the (Ta2O5)0.92-(TiO2)0.08 capacitor can be improved by one order of magnitude as compared to that of non-plasma-treated samples. The same result was also found in the alternative sputtering samples. The improvement was suggested to be due to the elimination of oxygen vacancies by oxygen plasma surface treatment or multistage deposition method. Furthermore, the dielectric properties of (Ta2O5)0.92-(TiO2)0.08 films were found to be remarkably sensitive to the post-annealing duration. The dominant conduction mechanism changed from Schottky Emission at low electric field to Poole-Frenkel at high electric field.
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張文豪. "Characterization of MoS2–graphene and MoS2–TiO2 composite films as counter electrodes in dye-sensitized solar cells." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/8sf6h3.
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碩士<br>國立彰化師範大學<br>光電科技研究所<br>102<br>The effect of annealing on the optoelectronic and electrical properties of MoS2 films was examined. The MoS2 film was annealed in the ambient nitrogen and vacuum, respectively. The crystallinity can be enhanced while annealing in vacuum. However, annealing in pure nitrogen ambient could make some of nitrogen incorporation into MoS2, resulting in the degraded crystallinity. A link between the electrical property, crystallinity and annealing temperature of the MoS2 film was established. In addition, the MoS2-graphene and MoS2-TiO2 composite films were characterized as the counter electrodes for Pt-free dye-sensitized solar cells (DSSCs). It is shown that the MoS2-graphene (MoS2-TiO2) counter electrode has a noticeable effect on the power conversion efficiency of DSSCs. A direct link between the power conversion efficiency of DSSCs and the transfer resistance of the MoS2-graphene (MoS2-TiO2) counter electrode was established.
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Chen, Jin-cheng, and 陳錦誠. "Characterization of Al2O3-TiO2 composite oxide films as the gate insulator layers prepared by solution-based process." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/35943239841571154566.
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碩士<br>逢甲大學<br>材料科學所<br>96<br>This study successfully prepared Al2O3-TiO2 thin films by sol-gel process. Al2O3-TiO2 thin films have been deposited via spin coating from aqueous solution and utilized as gate insulator in TFT. Precursor solutions were prepared by the same functional group (or moieties) of metal Alkoxides. The same functional group will undergo the same or similar chemical reactions regardless of the size of the molecule. Aluminum sec-Butoxide and Titanium(IV) n-butoxide dissolved in ethanol as a solvent and acetylacetone , AcA as a chelating agent under vigorous stirring for 30 min, followed by the drop wise addition of a deionized water for hydrolysis and HNO3 as a catalyst. All the syntheses were carried out at room temperature under vigorous stirring condition.
Al2O3-TiO2 thin films were prepared by depositing from fresh precursor solution on bare glass or ITO. Al2O3-TiO2 thin films are atomically smooth, dense, and amorphous, while exhibiting excellent morphologica stability to 400℃~500℃. It is evident that the transmission coefficient was approximately 91％ for both the treated films in the visible region. Al2O3-TiO2 thin films have low leakage current by electrical measurements. A leakage current density of 1.635×10-9 A/cm2 at 5V and 5.097×10-8 A/cm2 at 1 MV/cm and current limited breakdown field up to 3.12 MV/cm. The dielectric constant increased by increasing TiO2 ratios after 500℃ annealing and annealing temperature increased. The dielectric constant (εr) of 2.99 to 36.72 measured at 100 kHz.
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Wu, Yung-Chi, and 吳永企. "Characteristics of (TiO2)x(Ta2O5)1-x composite films prepared by Radio Frequency Ion Beam Sputtering Deposition." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/62117878190078966233.
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碩士<br>國立中央大學<br>光電科學研究所<br>94<br>Since the coating materials are limited, mixing materials provide the way to solve the limitation. In this study (TiO2)x(Ta2O5)1-x composite films were prepared by radio frequency ion-beam sputtering deposition (RF-IBSD) of Ta and Ti targets . The symbol “x” indicate the composite fraction of TiO2 。The composite films were all amorphous structure. The refractive indices and the extinction coefficients decreased with increase of Ta2O5 in composite films. The refractive indices of composite films ranged from 2.48 to 2.16 at 550-nm wavelength. The holes was observed at surface of pure TiO2 film , the residual stress of which was -0.516 GPa. There were crystals in the pure TiO2 film after annealing at 300℃.When the fraction of Ta2O5 is above 21% in the composite films，the holes observed at surface of pure TiO2 film disappeared, and the residual stress of the composite films decrease to -0.269 GPa; the structure of composite films remained amorphous to 350℃ annealing temperature. The (TiO2)x(Ta2O5)1-x composite films have good thermal stability, and decrease residuals stress and extinction coefficient .