Download or read book Nonlinear Optical Studies of Self assembled Monolayers SAM Silica SAM water Interface Probed with Second Harmonic Generation written by Kenneth Edward James and published by . This book was released on 2009 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Recognizing Molecules and Following Reactions at Interfaces Using the Nonlinear Optical Techniques Sum Frequency Generation and Second Harmonic Generation written by Zhiguo Li and published by . This book was released on 2015 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silica has been widely used as a solid support to generate functionalized silica in material science, which plays important roles in various areas such as catalysis and disease diagnostics. The applications of functionalized silica involve the special molecular properties of interfaces, which can differ from the properties of molecules in bulk phases. Nonlinear optical techniques, including second harmonic generation (SHG) and sum frequency generation (SFG), are a class of well-defined spectroscopic techniques that are well-suited to probe interfacial molecules and to study interfacial phenomena. Owing to their surface specificity, only the molecules that are ordered at the interface are probed in the measurement while interference from molecules in bulk phases is effectively excluded. Taking planar silica and functionalized planar silica as substrates, this thesis mainly focuses on characterizing the structure and order of molecules at these solid surfaces, and investigating the interaction between immobilized molecules and bulk phase molecules. Specifically, the binding of a model reactant 4-nitroacetophenone with amino and ureido organocatalytic monolayers on silica was investigated at the silica/acetonitrile interface using a combination of SHG and SFG, and the results reveal that the performance of immobilized catalysts is strongly affected by the local environment of surface molecules. Next, the Cu(I)-catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) was followed at the silica/methanol interface using vibrational SFG; the reaction order with respect to copper catalyst was determined to be 2.1, suggesting that two coppers are involved in the rate-determining step of the interfacial reaction. Using a CuAAC attachment strategy, the thermal evolution of immobilized DNA single strands and duplexes were investigated at the silica/buffer interface using vibrational SFG. Consistent with our SHG work, the melting temperature of the immobilized T15:A15 (thymidine 15-mer: deoxyadenosine 15-mer) duplex at the interface is found to be ~ 12 °C lower than the solution phase melting temperature, indicating immobilization on silica destabilizes the DNA duplex. Finally, as silica is a commonly used stationary phase in chromatography, the organization of acetonitrile molecules at the silica/aqueous interface was studied using vibrational SFG. For a given solution composition, increasing the solution pH is found to effectively decrease the number density of interfacial acetonitrile molecule, which we attribute to the decrease in the number density of surface silanol which can form a hydrogen bond with cyanide within the acetonitrile molecule. Overall, these results demonstrate the study of interfacial phenomena involving self-assembled monolayers on insulated surfaces like silica using the nonlinear optical techniques SHG and SFG. The combination of these techniques represents a useful approach to explore similar systems in their relevant research areas.

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2566 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 862 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 2000 with total page 868 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tuning Surface Properties Using Self assembled Monolayers for Various Applications written by Yekaterina Leonidovna Lyubarskaya and published by . This book was released on 2014 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The research presented in this dissertation focuses on the study of self-assembled monolayers (SAMs) in the modification of surface properties of different substrates for various applications. Self-assembled monolayers are organic molecules that can be deposited on a variety of surfaces, such as those of metals, metal-oxides, and semiconductors. Formation of SAMs on any inorganic material provides a ubiquitous way to impart desirable chemical and physical properties of organic and biological molecules to the inorganic substrate. It has been demonstrated that single molecules and their self-assembled monolayers can significantly alter the physical and electronic properties of inorganic conductors; moreover, studies have shown that the performance of many electrical devices can be transformed by modifying inorganic electrodes with organic SAMs. This is especially important for the development of next generation of ultra-compact electronic devices, in which the ability to control the interfacial charge-transport with a single monolayer of organic molecules would be ideal. We have developed different organic electronic architectures as test beds for studying the effect of monolayer properties, such as structural and geometrical parameters, on their electronic properties. By using a typical organic electronic device as a sensitive test platform, slight changes in a monolayer property, such as length, have been detected by studying the current- voltage characteristics (JV) of organic diodes functionalized with self-assembled monolayers (SAMs) of varying alkyl chain-length. Next, we describe the application of SAMs based on n-octylphosphonic acid (C8PA) and 1H,1H,2H,2H-perfluorooctanephosphonic acid (PFOPA) as anode buffer layers in C60-based organic photovoltaic (OPV) devices. We used the OPV platform to compare stabilities of organic monolayers exposed to ambient conditions with SAMs positioned inside working OPV devices. We found that the stabilities are different, suggesting the degradation mechanisms are distinct. The degradation of the OPV efficiency with respect to air exposure was significantly reduced with the perfluorinated PFOPA compared to the aliphatic C8PA. We attributed the OPV degradation to moisture diffusion from the top aluminum electrode and we discuss that the lowering of the anode work function is the result of hydrolysis of the SAM buffer layer. Next, we demonstrated the dependence of molecular electronic properties on the functional group substitution and that the changes in these properties can be measured using the organic light-emitting (OLED) platform. Specifically, we compared bilayered organic monomolecular systems immobilized on an inorganic electrode as the charge-injecting components of the organic light emitting diodes (OLEDs). Our bilayered interfaces comprise ordered inert primary and functional reactive layers, and they differ in only one parameter: the molecular structure of the terminal functional group. We demonstrate that we can visualize the differences in the charge transfer dynamics of two bilayered systems via patterned electroluminescence. In addition, we describe a new protocol for the preparation of shape-controlled multicomponent particles comprising metallic (Au and Ti), magnetic (Ni), and oxide (SiO2, TiO2) layers. First, we discuss the application and attractiveness of the colloidal structures, Janus Particles (JPs), that possess two different surfaces, varying either in polarity, hydrophilicity, etc. Next, we present our method for specifically controlling the composition, shape, and size of the micro-JPs. We demonstrate how this protocol permits fabrication of non-symmetrical particles by orthogonally functionalizing their opposite sides using well-established organosilanes and thiol chemistries (based on SAMs). We propose that these colloids may be used as convenient materials for studying non-symmetrical self-assembly at the meso- and micro-scales, due to their unique geometries and surface chemistries"--Pages viii-x.

Download or read book Optical Second Harmonic Generation Studies of the De Electric Field Screening in Si SiO2 Multiple Quantum Wells written by V. V. Savkin and published by . This book was released on 1999 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dc-electric field screening in the Si-SiO2 multiple quantum wells is studied by optical second harmonic generation. Experimentally observed oscillations in the nonlinear response. Inconsistent with semiclassical description of screening, are explained within the Tomas-Fermi approach.

Download or read book Spectroscopic Studies of Optical Second harmonic Generation from Si 001 Surfaces written by Yong Qiang An and published by . This book was released on 2003 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1994 with total page 1496 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Behaviour and Interactions of the Silica water Interface Studied Through Nonlinear Optics written by Benjamin Rehl and published by . This book was released on 2020 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Self Assembled Monolayers by Low Energy Reactive Ion Scattering Influences of Terminal Group Composition and Structure on Ion Surface Interaction written by Yang, Xi and published by . This book was released on 2007 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low energy (tens of eV) polyatomic cations were used as probes for characterization of monolayers of spontaneously chemisorbed thiols on gold. Characteristics including chemical composition, surface order and orientation of the self-assembled monolayers (SAMs) can be derived by monitoring the products of projectile ion neutralization, surface-induced dissociation (SID), and ion-surface reactions. To study the influence of the terminal group chemical structures and orientations of the SAMs on ion-surface interactions, a series of semi-fluorinated alkane thiols with difluoromethylenes buried underneath hydrocarbon terminal groups were examined (CH3CF2CH2− and CH3CH2CF2−). Compared to terminally fluorinated SAMs, they showed more projectile ion neutralization and less internal to vibrational energy deposition into precursor ions. Projectile ion-hydrocarbon reactions decreased significantly when difluoromethylenes are one or two bonds away from the terminal group. Furthermore, ion-surface reaction results on surfaces with odd and even chain lengths suggested that they have similar terminal methyl orientations to their hydrocarbon counterparts. Mixed monolayers of CF3CF2(CH2)14SH (F-SAMs) and CH3(CH2)15SH (H-SAMs) with systematically changing electron transfer, energy deposition and ion-surface reaction were prepared using mixed thiols solution and micro-contact printing (μ-CP). The solution mixture system showed linear variations in electron transfer and energy deposition with different F-SAM surface concentrations, while non-linear changes occur for ion-surface reaction suggesting strong lateral interactions between the two components. These interactions are minimized in theμ-CP system containing domains of each thiol. Energy deposition on the patterned surfaces varies non-linearly with changing F-SAM concentration which differs from the homogenously mixed system. To explore SID with a 90 collision angle, eV SID of a series of protonated peptide ions were performed in an in-line sector Time-Of-Flight (TOF) mass spectrometer. The results were compared to keV collision-induced dissociation (CID) data collected with the same instrument. Fragmentation efficiency for SID was higher than CID for those peptides. In addition to the excellent control over laboratory collision energies with SID, different amount of energy deposition can be achieved when varying surface composition, e.g. using mixed F-SAM/H-SAM. Reactive ion scattering spectrometry (RISS) results provided more in-depth knowledge of low energy ion-surface interactions that will promote usage of RISS as a novel surface characterization technique.

Download or read book The Second Harmonic generation Studies of Si SrTiO3 Interfaces written by Yelena V. Shirokaya White and published by . This book was released on 2001 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlinear Spectroscopy written by Società italiana di fisica and published by Elsevier Science & Technology. This book was released on 1977 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Self assembled Monolayers on Surfaces and at Interfaces written by Yenny Paola Cardona Quintero and published by . This book was released on 2014 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Materials Nanoarchitectonics written by Katsuhiko Ariga and published by Elsevier. This book was released on 2023-12-15 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt: Materials Nanoarchitectonics: From Integrated Molecular Systems to Advanced Devices provides the latest information on the design and molecular manipulation of self-organized hierarchically structured systems using tailor-made nanoscale materials as structural and functional units. The book is organized into three main sections that focus on molecular design of building blocks and hybrid materials, formation of nanostructures, and applications and devices. Bringing together emerging materials, synthetic aspects, nanostructure strategies, and applications, the book aims to support further progress, by offering different perspectives and a strong interdisciplinary approach to this rapidly growing area of innovation. This is an extremely valuable resource for researchers, advanced students, and scientists in industry, with an interest in nanoarchitectonics, nanostructures, and nanomaterials, or across the areas of nanotechnology, chemistry, surface science, polymer science, electrical engineering, physics, chemical engineering, and materials science. Offers a nanoarchitectonic perspective on emerging fields, such as metal-organic frameworks, porous polymer materials, or biomimetic nanostructures Discusses different approaches to utilizing "soft chemistry" as a source for hierarchically organized materials Offers an interdisciplinary approach to the design and construction of integrated chemical nano systems Discusses novel approaches towards the creation of complex multiscale architectures

Download or read book Experimental Relations of Gold and Other Metals to Light written by Michael Faraday and published by . This book was released on 1857 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Specific Ion Effects written by Werner Kunz and published by World Scientific. This book was released on 2010 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: Specific ion effects are important in numerous fields of science and technology. This book summarizes the main ideas that came up over the years. It presents the efforts of theoreticians and supports it by the experimental results stemming from various techniques.