The background and operation of charge transfer devices is reviewed, and a computer model simulation of focal plane arrays is presented. The model provides an option to predict the performance of a focal plane. With this program, any of the allowed materials, detectors, readout structures, or preamplifiers that make up a focal plane, may be selected to create new designs for analysis. Only surface channel devices are considered, and only references to the spectral dependence are presented. The computer model's operation and validity is supported by over 70 equations and more than 50 figures, including actual computer screen printouts. Standard equations followed by brief discussions are used to support the menu driven program. The structure and operation of the computer model is presented, but not the actual software source code.

The evolution of the present work began with the syntheses of novel bis(alkylimino)acenaphthene (BIAN) ligands. At the outset of this research, despite the presence of dozens of aryl-BIAN ligands in the literature, there were as of yet no reported BIAN ligands bearing alkyl substituents. Given the nearly ubiquitous use of transition metal complexes of alkyl diazabutadiene (DAB) ligands for e.g. catalysis and as ligands for carbene chemistry, interest was generated in developing this emerging field of synthetic chemistry. Initial studies focused on the synthesis of alkyl-BIAN ligands since the traditional synthetic approaches that had been developed for aryl-BIAN ligands were unsuccessful for the alkyl analogues. As an alternate synthetic route, it was decided to employ amino- and imino-alane transfer reagents which had previously proved successful for the conversion of C=O into C=N-R functionalities. While this transfer route had proved successful to synthesize moderate yields of highly fluorinated DAB ligands, it was unknown how or whether this methodology would apply in the case of alkylated BIAN systems. Over the past decade, there has been a surge of interest regarding lanthanide complexes that are capable of undergoing spontaneous electron transfer processes. There are several reports in the literature that describe the ability of Ln(II) ions to undergo spontaneous oxidation, thereby causing one-electron reduction of the coordinated ligand and generally resulting in the corresponding Ln(III) complex. The present work focused on an enhanced understanding of the electronic communication between the lanthanide and the attached ligand. Particular emphasis was placed on defining the resulting oxidation states and the manner in which delocalized electrons of the radical anion species travel over a conjugated system. This fundamental information was gleaned from single-crystal X-ray diffraction studies and magnetic moment measurements that were obtained using the Evans method. Additional insights stemmed from the use of more classical techniques such as IR and NMR spectroscopy. In favorable cases, the presence or absence of spectral peaks can permit assignment of the lanthanide oxidation state. Accordingly, the research plan was to synthesize a series of BIAN-supported decamethyllanthanocene complexes with the goal of learning how to control the spontaneous charge transfer that had been reported in the literature. A longer term goal was to develop a bifunctional ligand of the BIAN type that was capable of accommodating two lanthanide or main group element moieties. Systems with tunable electronic interactions between lanthanide or main group elements are of interest because they offer the prospect of extended delocalization of electron density. Systems of this type have potential applications as e.g. molecular wires and single-molecule magnets. Indeed, such systems have been investigated by using bis(bipyridyl) and bis(terpyridyl) ligands to support two redox-active moieties. However, in the present work, it was recognized that a bifunctional BIAN-type ligand might be of considerable interest as the supporting structure for studying the communication between lanthanide or main group element moieties. A synthesis of variously substituted tetrakis(imino)pyracene (TIP) ligands was therefore undertaken. The flat, rigid nature of the TIP ligands rendered them ideal scaffolds for studying the redox behavior and electronic communication between lanthanide or main group element centers. The new TIP ligand class also proved to be useful for the assembly of the first example of a metallopolymer based on a BIAN-type ligand. / text

The investigations described within this dissertation foretell the imminent revolution in optical analytical spectroscopy and conclusively demonstrate superior qualitative and quantitative analysis performance of a new system for atomic spectroscopy as compared to present, state-of-the-art instrumentation. The advent of a new class of multichannel detectors, the silicon charge transfer devices (CTDs) is shown to significantly impact ultraviolet, visible, and near-infrared analytical spectroscopy. An overview of the operation, characteristics, and performance of CTDs is presented including the results of the characteristics of a CTD detector system developed during these investigations. Theoretical comparisons of the performance obtainable in spectroscopic systems employing CTD detectors versus conventional detectors, including equations identifying the factors limiting sensitivity, demonstrate that CTDs offer superior performance. The second part of this dissertation describes the application of a particular CTD, the charge injection device (CID), to a very challenging spectroscopic problem, as far as light detection is concerned, simultaneous multielement analytical atomic emission spectroscopy. This widely employed technique for qualitative and quantitative elemental analysis requires sensitive and wide dynamic range detection of a large number of spectral resolution elements. This research resulted in the development of a novel echelle spectrometer employing a CID detector which has been demonstrated to be capable of solving many of the problems currently encountered in analytical atomic spectroscopy. The system achieves superior sample throughput rates, flexibility, accuracy and precision as compared to sequential spectrometers employing a single detector and to polychromators employing relatively few fixed detectors. The research included the development of a unique method of operating the CID, which is used to cope with the very wide dynamic range signals encountered in atomic spectroscopy, and has resulted in a spectroscopic instrument able to qualify simultaneously major and trace components of extremely complex samples with greater sensitivity and accuracy than possible with conventional instrumentation. New, very flexible, and extremely rapid methods of qualitative analysis have also been developed which virtually eliminate the possibility of spectral line misassignment. The atomic emission spectroscopic system is applicable in a variety of analytical areas as diversified as high sensitivity detection of near infrared spectral lines and element-specific detection of chromatographic eluents.

The ease of electron loss of fifty alipathic thioethers was studied by electrochemistry, charge transfer and photoelectron spectroscopy. These compounds consisted of mesocyclic thioethers and S-methyl norbornane derivatives. Comparison of charge transfer and photoelectron ionization potential showed a good correlation. Correlation of ionization potential with anodic peak potentials showed the existence of two groups of compounds. Those compounds having an electron rich neighboring group capable of an intramolecular interaction were found to have a good correlation of ionization potential with electrochemical peak potential. For those compounds without this capability, no observable correlation was seen. Photoelectron ionization potentials of thioethers are a function of the alkyl groups attached to the sulfur atom. With substituent constants assigned to alkyl groups from measurements on simple thioethers, the ionization potential of more complicated thioethers can be calculated. Compounds whose experimental value was found to be less than the calculated value were found to fall in the group where an intramolecular neighboring group could facilitate the ease of electron loss by stabilization of the cation radical. Electrochemical peak potentials were seen to be dramatically affected by intramolecular stabilization of the cation radical. Shifts of 600-800 mV were seen for structurally similar compounds whose only difference was the availability of an electron rich neighboring group. Since the electrochemistry of these compounds exhibits irreversible behavior, the shift in peak potential could be due to a change in the formal potential, the heterogeneous rate constant, the rate of a following chemical reaction or a combination of these. Changes in the heterogeneous rate constant or chemical step rate constant alone cannot account for the magnitude of the shift seen. Thus the differences observed must be due to two different processes. In the noninteracting case, E⁰' is a measure of the formation of the cation radical, whereas, in the case of interacting compounds E⁰') is a measure of the formation of an intramolecularly stabilized cation radical where bond formation has occurred. Evidence for the structure of some intramolecular stabilized intermediates is presented. An electron deficient thioether which is a model for biological systems was shown to be capable of phosphorylating adenine nucleotides.

Organic materials such as phthalocyanine-based systems present a great potential for organic device applications due to the possibility of integrating films of different organic materials to create organic heterostructures which combine the electrical capabilities of each material. This opens the possibility to precisely engineer and tune new electrical properties. In particular, similar transition metal phthalocyanines demonstrate hybridization and charge transfer properties which could lead to interesting physical phenomena. Although, when considering device dimensions, a better understanding and control of the tuning of the transport properties still remain in the focus of research. Here, by employing conductive atomic force microscopy techniques, we provide an insight about the nanoscale electrical properties and transport mechanisms of MnPc and fluorinated phthalocyanines such as F16CuPc and F16CoPc. We report a transition from typical diode-like transport mechanisms for pure MnPc thin films to space-charge-limited current transport regime (SCLC) for Pc-based heterostructures. The controlled addition of fluorinated phthalocyanine also provides highly uniform and symmetric-polarized transport characteristics with conductance enhancements up to two orders of magnitude depending on the polarization. We present a method to spatially map the mobility of the MnPc/F16CuPc structures with a nanoscale resolution and provide theoretical calculations to support our experimental findings. This well-controlled nanoscale tuning of the electrical properties for metal transition phthalocyanine junctions stands as key step for future phthalocyanine-based electronic devices, where the low dimension charge transfer, mediated by transition metal atoms could be intrinsically linked to a transfer of magnetic moment or spin. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Two novel materials have been developed: TiO2/poly(dimethylsiloxane) (PDMS) beads as buoyant photocatalyst materials for water remediation, and copper rhodamine‑B silane (Cu‑RBS) as an n ‑type organic/inorganic hybrid for thermoelectric applications. The approach to incorporate TiO2 into low‑density PDMS beads addresses many of the challenges traditionally encountered when creating buoyant photocatalysts, an area which is crucial for wide‑spread remediation of water resources, including natural bodies of water. The performance and reusability of the buoyant photocatalyst materials, demonstrated by using methylene blue as a model degradation target, is strong enough for environmental application. The use of a kinetic model and the introduction of a parameter to allow comparison of buoyant photocatalysts is also included as part of the analysis. The performance of Cu‑RBS was investigated as a low‑temperature thermoelectric material. Clear improvements in the electrical conductivity and Seebeck coefficient are observed for RBS upon coordination to Cu2+. Evidence explaining this improvement is provided by computational analysis and by concentration‑dependent optical absorption and fluorescent emission measurements, all of which indicate that a metal‑to‑ligand charge transfer occurs from Cu2+ to RBS. Although the power factor of Cu‑RBS is low compared to other materials reported in the literature, these results provide a promising approach to increasing both the Seebeck coefficient and electrical conductivity of n‑type small molecule organic systems.

Methods to advance the understanding of water and other aqueous systems are devel- oped. This work falls into three areas: The creation of better interaction potentials for water, improved methods for sampling configurational space, and the applications of these methods to understand systems of interest. Charge transfer has been shown by ab initio methods to be important in the water–water and water–ion interactions. A model for treating charge transfer in liquid water and aqueous systems is presented in this manuscript. The model is called Discrete Charge Transfer (DCT) and is based on the commonly-used TIP4P/2005 model, which represents the charge distribution of water molecules with three charge sites. Such models have been very successful in reproducing many of the physical properties of water. Charge transfer is introduced by transferring a small amount of charge, -0.02e, from the hydrogen bond acceptor to the hydrogen bond donor, as has been indicated by electronic structure calculations. We have parameterized both polarizable and non-polarizable potentials, optimized to include charge transfer. Methods to surmount the obstacles incurred by the introduction of charge transfer, which involve the amount of charge transfer at large distances and implementation into Molecular Dynamics simulation, is presented, along with our results assessing the importance of charge transfer in liquid water and aqueous systems. Also presented is a method for improving eciency of a sampling technique, Replica Exchange, by reducing the number of replicas. The improved method is called Replica Exchange with Driven Scaling (REDS2).

The presence of charge transfer (CT) interactions is clear in a variety of systems. In CT, some electron density is shifted from one molecule to another (non-bonded) molecule. The importance of this CT interaction is unclear. Previous attempts to look at the conse- quences of CT required the use of ab initio molecular dynamics (AIMD), a computationally intensive method. Herein, a method for including CT in force field (FF) simulations is described. It is efficient, produces charges in agreement with AIMD, and prevents long- ranged CT. This CT MD method has been applied to monatomic ions in water. When solvated, ions do not have an integer charge. Anions give up some electron density to their ligands, and cations receive some electron density from their ligands. In bulk, the first solvation shell does not compensate for all CT, i.e. the charge is not smeared out over the first solvation shell. Rather, some charge is also found in the second solvation shell and further into the bulk. The charge of the first solvation shell depends on the balance between ion-water and water-water CT. When an interface is present, the charge outside of the second solvation shell will reside at the interface. This occurs even when the ion is over 15 Å away from the surface. The effect of long-ranged CT is mediated by changes in the hydrogen bonding patterns in water induced by the ions (not direct CT from the ions to distant waters). The model has also been applied to water’s ‘‘self-ions’’ hydronium and hydroxide. Trajectories from the multi-state empirical valence bond model (MS-EVB3) are analyzed. The differences between monatomic and molecular ions are explored. The direction of CT and the effect of hydrogen bonding with the ion are considered. The damping of CT as ligands are added is discussed and a method to improve the MD model, in order to account for damping, is proposed.

Wu, Xuefeng = 鉀摻雜碳氫分子膜的電荷轉移以及金屬薄膜中的贗能隙效應研究 / 吳雪峰. / Thesis Ph.D. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 103-114). / Abstracts also in Chinese. / Title from PDF title page (viewed on 14, September, 2016). / Wu, Xuefeng = Jia shan za tan qing fen zi mo de dian he zhuan yi yi ji jin shu bo mo zhong de yan neng xi xiao ying yan jiu / Wu Xuefeng.

" A series of symmetric and asymmetric 2-arylidene and 2,5-diarylidene cyclopentanone dyes have been synthesized. Their electronic absorption and fluorescence spectra have been measured in a wide variety of nonpolar and polar, aprotic and protic solvents. Absorption and fluorescence spectral maxima have been correlated with the ET(30) empirical solvent polarity scale. Lippert-Mataga analysis (in aprotic solvents) demonstrates the increase in the electronic dipole moment from the ground singlet to excited singlet states, consistent with the internal charge transfer (ICT) nature of the S0 --> S1 excitation. TD-DFT spectral calculations support the ICT natures of these compounds. Photophysical properties of these compounds involved measuring both fluorescence quantum yields and lifetimes in various solvents. Investigation of the deactivation kinetics involved determining the first-order radiative and nonradiative rates of decay upon knowledge of the quantum yield and lifetime data. Fluorescence quantum yields and lifetimes of the compounds studied varied depending on the nature of the solvent environments. Excited state protonation in acetic acid was observed for several 2,5-diarylidene cyclopentanones and deltapKa’s have been determined via the Forster Cycle. Thorough work on the photochemistry of (2E,5E)-2,5-bis(p-dimethylaminobenzylidene)-cyclopentanone (bis-dmab) was carried out, consisting of testing bis-dmab as a singlet oxygen photosensitizer, and examination of both the chemical reactivity of bis-dmab with singlet state oxygen (self-sensitized photooxidation) and (E,E) --> (E,Z) photoisomerization. "