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Surface Potential Measurements of Micropatterned Self-Assembled Monolayers (SAMs) on n-Si (111) via Kelvin Probe Force Microscopy / ケルビンプローブ力顕微鏡によるSi(111)表面に形成したSAMの表面電位計測GARCIA, MARIA CARMELA TAN 23 March 2022 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第23897号 / 工博第4984号 / 新制||工||1778(附属図書館) / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 杉村 博之, 教授 山田 啓文, 教授 邑瀬 邦明 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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Metal Oxide/Self-Assembled Monolayer Recombination Junctions for Monolithic Perovskite/Silicon Tandem Solar CellsYıldırım, Bumin Kağan 11 June 2023 (has links)
Solar photovoltaics (PV) is expected to be a critical contributor to mitigating
the effects of climate change by helping to satisfy net zero emissions. Since crystalline silicon-based solar cells are close to their practical efficiency limit, further
reducing the balance of system (BoS) costs is only possible by increasing the cell
efficiencies. The most promising candidate is perovskite/silicon (Si) tandem solar
cell technology, which allows efficient solar spectrum harvesting. This relatively
new technology attracts attention due to its potential to dominate the PV market; however, it also brings challenges that must be overcome, like stability and
scalability concerns.
This thesis project focuses on optimizing and characterizing recombination
junctions (RJs) for monolithic perovskite/Si tandem solar cells aimed at improved
performance and stability. Tandem solar cell PV parameter measurements, encapsulated stability measurements, and thin film characterizations are performed
for RJ developments. The optimizations are performed for tandem solar cells
with solution-processing and hybrid methods. Self-assembled monolayer (SAM)
molecules and transparent conductive oxide (TCO) recombination layer (RL)
combinations are optimized to obtain tandems with hybrid technique.
In addition, the influence of the thickness of TCO RL on the tandem devices’
performance is also investigated, particularly solution-processed tandems. The
improvements are observed by thinning down the thickness of TCOs regardless
of the material type.
3
Characterizations revealed that ultra-thin ( 5 nm) amorphous indium zinc
oxide (IZO) RL allows more workfunction shift, homogeneous surface potential
distribution with SAM deposition, and better carrier recombination suppression
at the perovskite/hole transport layer (HTL) interface.
Ultra-thin RL idea is combined with some optical improvements in the device
architecture, and stable high-efficient perovskite/Si tandem solar cells with 32.5%
power conversion efficiency (PCE) and 80% fill factor (FF) values are realized.
In addition, the preliminary examples of tandem devices with a larger active area
(4 cm2
) are presented. Finally, the remaining challenges and alternative concepts
are also discussed.
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Fabrication of Chemically Modified Nanometer-sized Gold Electrodes and Their Application in Electrocatalysis at Pt Nanoparticles.Lakbub, Jude 17 December 2011 (has links) (PDF)
Hydrogen evolution via proton reduction occurs at a high rate at the surface of Pt than at Au electrodes. Using cyclic voltammetry, chemically modified nanometer-sized Au electrodes, prepared by the Laser-Assisted Puller Method, were employed to examine current amplification by electrocalysis at Pt nanoparticles adsorbed on the modified Au electrode surfaces. The electrodes were modified with Self-Assembled Monolayers (SAMs) of cysteamine and soaked in Pt colloid solutions overnight. Monitoring the decrements of the characteristic steady-state catalytic current for proton reduction indicated that aggregates of Pt nanoparticles are adsorbed on the cysteamine monolayers and desorb from them particle by particle. The results also indicate that some particles are strongly attached to the modified electrode surface and do not deplete even after thorough rinsing.
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Development And Application Study Of Nanoscale Thin Film Materials And Polymer NanocompositesChen, Hui 01 January 2008 (has links)
This dissertation demonstrated that the manipulation of substances at the molecular or nanometer level can lead to the discovery and development of new materials with interesting properties and important applications. Chapter 1 describes the development of a nanoscale molecular thin film material for corrosion protection. By using a self-assembled monolayer film with a thickness of only about 1 nanometer as a linkage, a covalent bonding was achieved between a polyurethane top coating and an aluminum alloy substrate. This covalent bonding between polymer top coating and the aluminum alloy substrate significantly improved the corrosion resistance of the substrate. Chapter 2 and Chapter 3 describe the development of a gold nanoparticle-polymer composite material in different forms with a number of applications. Gold nanoparticles are among one of the most extensively studied nanomaterials. When the size of gold is shrunk to the nanometer scale, many interesting and new physical properties start to appear from gold nanoparticles. The optical properties of gold nanoparticles, particularly the surface plasmon resonance absorption, have been investigated in this dissertation for the development of multifunctional nanocomposite materials. Chapter 2 presents the preparation of a gold nanoparticle/poly(methyl methacrylate) (PMMA) nanocomposite film and the application of such films for microstructure fabrication using a direct laser writing technique. Gold nanoparticles are excellent photon-thermal energy converters due to their large absorption cross section at the surface plasmon resonance region. Upon laser irradiation of the nanocomposite film, the thermal energy converted from the absorbed photon energy by gold nanopaticles induced a complete decomposition of PMMA, leading to the formation of various microstructures on the nanocomposite films. Chapter 3 reports the further development of a nanoparticle/polymer composite nanofiber material fabricated through an electrospinning process. The matrix of the nanofiber is made of two polyelectrolytes, poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH). Three methods were developed to incorporate gold nanoparticles into the polymer matrix. The composite nanofiber materials developed in this study demonstrate multifunctional properties, including good electrical conductivity, photothermal response, and surface-enhanced IR absorption. This material may be used for many important applications including catalysis, chemical and biological sensors, and scaffold materials for tissue engineering. In Chapter 4, another most important nanomaterial, carbon naotubes (CNTs), were introduced as fillers to prepare polymer nanocomposites. A dispersion method for multi-walled carbon nanotubes (MWCNTs) using a conjugated conducting polymer, poly(3-hexylthiophene) (P3HT) as the third component and trifluoroacetic acid (TFA) as a co-solvent was developed. Due to the excellent dispersion of carbon nanotubes in PMMA and enhanced conductivity of the nanocomposites by the conjugated conducting polymers, the prepared composite materials has an extremely low percolation threshold of less than 0.006 wt% of MWCNT content. The potential use of MWCNT/conducting polymer composites for energy storage applications such as suppercapacitors was further investigated by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and charging-discharging cycles. Compared to pure carbon nanotubes, the nanocomposite materials have significantly improved properties and are promising for supercapacitor applications.
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Molecular Ordering, Structure and Dynamics of Conjugated Polymers at Interfaces: Multiscale Molecular Dynamics SimulationsYimer, Yeneneh Yalew January 2014 (has links)
No description available.
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Self-assembled Photo-responsive Nanostructures for Smart Materials ApplicationsLiu, Mengmeng 23 October 2017 (has links)
No description available.
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Development of a planar immunoFET which detects protein analyte in high salt environmentsGupta, Samit Kumar 16 December 2010 (has links)
No description available.
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Fundamentals and Applications of Visible Plasmonics: from Material Search to Photoluminescence Enhancement / 可視プラズモニクスの基礎と応用:物質探索から発光増強までTakekuma, Haruka 23 May 2022 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第24074号 / 理博第4841号 / 新制||理||1692(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 寺西 利治, 教授 島川 祐一, 教授 倉田 博基 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
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Development of Polyphenolic Nanoparticles for Biomedical ApplicationsCheng, Huaitzung Andrew January 2016 (has links)
Polymeric nanoparticles have a wide range of applications, particularly as drug delivery and diagnostic agents, and tannins have been regarded as a promising building block for redox and pH responsive systems. Tannins are a class of naturally occurring polyphenols commonly produced by plants and are found in many of our consumables like teas, spices, fresh fruits, and vegetables. Many of the health benefits associated with these foods are a result of their high tannin contents and the many different types of tannins found in various plants have demonstrated therapeutic potentials for conditions ranging from cardiovascular disease and diabetes to ulcers and cancer. Diets rich in tannins have been associated with lower blood pressure in patients with hypertension. The plurality of phenols in tannins also makes them powerful antioxidants and as a result, there is a lot of interest in taking advantage of their self-assembling abilities to make redox and pH responsive drug delivery systems. However, the benefit of natural tannins is limited by their instability in physiological conditions. Furthermore, there is limited control over molecular weight and reactivity of the phenolic content of plant extracts. Herein we report the novel synthesis of pseudotannins with control over molecular weight and reactivity of phenolic moieties. These pseudotannins have can form nanoscale interpolymer complexes under physiological conditions and have demonstrated antioxidative potential. Furthermore, pseudotannin IPCs have been shown to be responsive to physiologically relevant oxidation as well as the ability to easily incorporate cell targeting peptides, fluorescent tags, and MRI contrast agents. The work presented here describes how pseudotannins would be ideally suited to minimally invasive techniques for diagnosing atherosclerotic plaques and targeting triple negative breast cancer. We demonstrate that pseudotannin can very easily and quickly form nanoscale particles that are small enough to be uptaken into mammalian cells. Furthermore, by self-assembling with gadolinium, pseudotannins can effectively attenuate the signal of gadolinium based MRI contrast agents. This in conjunction with oxidation responsive decomplexation could be a viable option for diagnosing the severity and risk of rupture of atherosclerotic plaques. Also, we demonstrate that pegylated compounds can easily be incorporated into pseudotannin nanoparticles to impart cell targeting functionality. The subsequent uptake of pseudotannin nanoparticles into breast cancer cells demonstrated the ability to increase their sensitivity to UV radiation. The creation of synthetic tannin-like polymers leads to directly to making a variety of self-assembling, stimuli responsive, and bioactive nanoparticles well-suited for various biomedical applications. / Bioengineering
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PROPERTIES AND MOLECULAR INTERACTIONS OF TWO-DIMENSIONAL NUCLEIC ACID NANOASSEMBLIES: IMPLICATIONS FOR BIOSENSING AND DIAGNOSTICSRedhu, Shiv Kumar January 2014 (has links)
There is a need for the development of new technologies for the early detection of disease. Diverse initiatives are underway in academia and the pharmaceutical and biotechnology industries to develop highly-sensitive, high-throughput methods to detect disease-relevant biomarkers at the single-cell level. Biomarkers can define the progress of a disease or efficacy of disease treatment, and can include nucleic acids (RNA, DNA), proteins, small molecules, or even specific cells. While discovery research in this area is accelerating, there are a number of current experimental limitations. Most existing methodologies require a relatively large sample size. Also, amplification-based detection technologies are destructive to sample, and errors in amplification can occur, leading to an incorrect diagnosis. Nanomaterial-based devices (nanodevices) offer the promise of label-free, amplification-free detection strategies. Such nanodevices could allow analysis of minute biological samples without the requirement for amplification or incorporation of reporter groups. Loss of sample, due to handling and processing would be minimized and the sample could be recovered for further analysis. Atomic force microscopy (AFM) allows topographic imaging and compressibility/elasticity measurement of biomolecules on solid supports. AFM can enable assays of ligand binding with single molecule detection capability. Certain nucleic acid types, in particular double-stranded (ds) RNA, can act as a biomarker for specific cancers (e.g. leukemia) and viral infection. dsRNA also is of interest since it is a conserved structural feature of precursors to gene-regulatory RNAs, including micro (mi) RNAs and short interfering (si) RNAs. This project demonstrates a single-step, label-free, amplification-free approach for detecting the interaction of biomolecules that bind and/or process dsRNA, using a nanomanipulated, self-assembled monolayer (SAM) of a ds[RNA-DNA] chimera as imprinting matrix, a reference nuclease as imprinting agent, and AFM for imprint-readout. The action of the dsRNA-specific enzyme, ribonuclease III (RNase III), as well as the binding of an inactive, dsRNA-binding RNase III mutant can be permanently recorded by the input-responsive action of a restriction endonuclease that cleaves an ancillary reporter site within the dsDNA segment. The resulting irreversible height change of the arrayed ds[RNA-DNA] chimera, as measured by atomic force microscopy, provides a distinct digital output for each type of input. These findings provide the basis for developing imprinting-based nano-biosensors, and reveal the versatility of AFM as a tool for characterizing the behaviour of highly-crowded biomolecules at the nanoscale. RNA-DNA heteroduplexes are biomarkers for specific inflammatory conditions of genetic origin, and also are the product of capture of an RNA (e.g., miRNA) by a complementary DNA sequence. The approach used here to detect RNA-DNA hybrids is based on the ability of alkylthiol-modified ssDNA molecules to form monolayers and nanomatrices on gold surfaces (as described above) with density-dependent thickness, which increases upon formation of RNA-DNA hybrids following addition of a complementary oligoribonucleotide. Changes in hybrid matrix thickness can be measured by AFM, using a reference monolayer. RNA-DNA hybrid formation as well as subsequent processing by RNase H can be observed as a height increase or decrease, respectively, of the monolayer. When Mg2+ is omitted to prevent RNA cleavage, but not protein binding, a significant height increase is observed. The height increase is not observed with the corresponding ssDNA or ssRNA nanomatrices, and only occurs with nanomatrices having a hybrid density above a defined threshold. The data indicate formation of a stable multimeric RNase H assembly on the hybrid nanomatrix which provides a robust signal that is nondestructive to the RNA. The implications of these findings are discussed with respect to development of novel detection methodologies for RNA, dsRNA, and RNA-DNA hybrids. / Chemistry
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