Дисертації з теми "Charge vs energy transfer"
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Gillespie, Peter N. O. "Theory of charge transfer in solar energy materials." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22771/.
Повний текст джерелаCanola, Sofia <1989>. "Modeling charge and energy transfer in organic molecular materials." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/8131/1/Canola_Sofia_tesi.pdf.
Повний текст джерелаHuang, Zhongjie. "Investigation of Interfacial Charge Transfer Processes in Energy Conversion Devices." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448663899.
Повний текст джерелаByrne, Ciaran Martin. "Energy loss and charge transfer effects of low energy protons in thin organic films." Thesis, Queen Mary, University of London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393732.
Повний текст джерелаBdžoch, Juraj [Verfasser]. "Ultrafast energy and charge transfer in D2O/Ru(0001) / Juraj Bdžoch." Berlin : Freie Universität Berlin, 2011. http://d-nb.info/1025169107/34.
Повний текст джерелаMutz, Niklas. "Energy and Charge Transfer at Hybrid Interfaces Probed by Optical Spectroscopy." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22797.
Повний текст джерелаHybrid inorganic/organic systems can combine the advantages of both materials such as high carrier mobilities in inorganic semiconductors and large light-matter interaction in organic ones. In order to benefit from these heterostructures, a thorough understanding of the interface is needed. Two processes occurring at the interface are looked at in this thesis. Förster resonance energy transfer (FRET) is studied between a single InGaN/GaN quantum well and the polymer Cn-ether PPV. Despite the large internal electric fields in the quantum well, efficient FRET is possible as long as other non-radiative decay channels are suppressed. This is shown by temperature dependent PL and PLE spectroscopy. PLE spectra clearly demonstrate an enhanced light emission from the acceptor. At elevated temperatures, non-radiative decay pathways become dominant. Excited-state charge transfer is studied on MoS2 in combination with the molecule H2Pc. The combination with molecules can extend the functionality of MoS2. Photoelectron spectroscopy (PES) reveals a type II energy level alignment at the MoS2/H2Pc interface. Excited electrons are transferred from H2Pc to MoS2, deduced from a shortening of the H2Pc PL decay time. Photocurrent spectra further show that the transferred electrons contribute to an enhanced photoconductivity. Additionally, bare 2D transition-metal dichalcogenides (TMDCs) are studied. In order to fabricate high-quality TMDC monolayers, a growth method was developed in-house. The grown monolayers are characterised by optical spectroscopy. The versatility of the method is demonstrated by the growth of alloys and heterostructures. The influence of the substrate dielectric function is investigated by comparing band-gaps measured by PES with the exciton transition energies obtained by reflectance measurements. An almost equal reduction in both energies with the substrate dielectric constant is seen.
Weber, Fabian [Verfasser]. "Structure-Property Relationships for Energy- and Charge-Transfer Processes / Fabian Weber." Berlin : Freie Universität Berlin, 2020. http://d-nb.info/1204429324/34.
Повний текст джерелаGuo, Fangyeong. "High energy excited states in conjugated polymers and charge-transfer solids." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186708.
Повний текст джерелаMenting, Raoul. "Light-induced energy and charge transfer processes in artificial photosynthetic systems." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16656.
Повний текст джерелаThe main objective of the present thesis was to conduct investigations of photo-induced electron transfer (ET) and excitation energy transfer (EET) processes in model compounds that are considered potentially appropriate for use in artificial photosynthesis. Two approaches have been used to construct the artificial photosynthetic systems, namely covalent and supramolecular approach. In both systems similar optically active molecules have been employed, particularly silicon-based phthalocyanines (SiPc). A comparative study between the covalently-linked and self-assembled systems had been conducted. For these purposes, thorough spectroscopic measurements in the UV/Vis range had been performed on these conjugates. A combination of steady-state and time-resolved experiments allowed an identification and quantification of the photo-induced ET and EET processes. In the first part of the work several covalently bound triads and a pentad bearing a central SiPc unit were studied. In all systems highly efficient ET and EET processes take place. It was found that the solvent exerts great influence on the photophysical properties of the systems. The lifetime of the charge-separated state varied from 1.7 ns (toluene) down to 30 ps (DMF). In the second part of the thesis, for the first time the formation of ternary supramolecular complexes consisting of a beta-cyclodextrin (CD), a conjugated subphthalocyanine (SubPc), a porphyrin (Por) and a series of SiPcs substituted axially with two CDs via different spacers was shown. These components are held in water by host-guest interactions and the formation of these host-guest complexes was found to be very efficient. Upon excitation of the SubPc-part of the complex sequential ET and EET processes from SubPc to SiPc take place. The Por dye acts as a transfer bridge enabling these processes. The probability of ET is controlled by the linker between CD and SiPc. Charge recombination to the ground state occurs within 1.7 ns.
Nam, Yoon Sung. "Nanostructures templated on biological scaffolds for light harvesting, energy transfer, charge transfer, and redox reactions." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/60784.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (p. 149-160).
Solar energy provides an unparalleled promise to generate enormous amounts of clean energy. As the solar industry grows rapidly with a focus on power generation, new, but equally important challenges are emerging, including how to store and transfer the generated solar energy. Light-driven water splitting to generate hydrogen has received increasing attention as a means of storing solar energy. However, in order to evolve hydrogen with no energy input beyond sunlight, it is important to develop a stable and efficient catalytic system for water oxidation, which is the more challenging half-reaction of photocatalytic water splitting. Over several billion years, cyanobacteria and plants have evolved highly organized photosynthetic systems for the efficient oxidation of water. Water oxidation by mimicking photosynthesis has been pursued since the early 1970s; however, the approaches have been primarily limited to the extraction and reconstitution of the existing natural pigments, photosystems, and photosynthetic organisms, which suffer from instability. Metal oxide catalysts, often coupled with pigments, are similar to the reaction centers in natural photosystems and have been shown to photochemically oxidize water. Unfortunately, various approaches involving molecular design of ligands, surface modification, and immobilization still show low catalytic efficiencies unless they are used under relatively harsh conditions (i.e., in highly alkaline or acidic solutions under ultraviolet radiation). The current work aims to demonstrate the impact of nano-scale assembly of organic and inorganic molecules on energy and charge transfers, and related redox reactions. Genetically modified M13 viruses are explored as biological scaffolds to guide the formation of metal oxide catalysts-pigments hybrid nanostructures that enable efficient transports of both energy and electrons for photochemical water oxidation. This dissertation deals with three aspects of the virus-templated nanostructures - photonic, photochemical, and electrochemical properties. First, organic pigments are arranged into a one-dimensional light-harvesting antenna on the M13 virus. Chemical grafting of zinc porphyrins to the M13 virus induces spectroscopic changes, including fluorescence quenching, the extensive band broadening and small red-shift of their absorption spectrum, and the shortened lifetime of the excited states. Based on these optical signatures a hypothetical model is suggested to explain the energy transfer occurring in the supramolecular porphyrin structures templated on the virus. Second, through further genetic engineering of M13 viruses, iridium oxide hydrosol clusters (catalysts) are co-assembled with zinc porphyrins. When illuminated with visible light, this system evolves about 100 oxygen molecules per surface iridium molecule per minute in a prolonged manner. In addition, porous polymer microgels are used as an immobilization matrix to improve the structural durability of the assembled nanostructures and enable the recycling of the materials. The system also maintains a substantial level of its catalytic performance after repeated uses, producing about 1,200 oxygen molecules per molecule of catalyst during 4 cycles. These results suggest that the multiscale assembly of functional components, which can improve energy transfer and structural stability, should be a promising route for significant improvement of photocatalytic water oxidation. Lastly, electrochemical properties of the virus-templated iridium oxide nanowires are examined as an electrochromic film on a transparent conductive electrode. The prepared nanowire film has a highly open porous morphology that facilitates ion transport, and the redox responses of the nanowires are limited by the electron mobility of the nanowire film. These results demonstrate that a bio-templating approach provides a versatile platform for designing complex nanostructures that can facilitate the transport of electrochemical molecules in a broad range of photoelectrochemical devices.
by Yoon Sung Nam.
Ph.D.
Hu, He. "INFRARED STUDY OF CHARGE TRANSFER BETWEEN ORGANIC MOLECULES AND SEMICONDUCTORS." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1522444435463025.
Повний текст джерелаRay, Matthew Preston. "The dynamics of energy and charge transfer in low and hyperthermal energy ion-solid interactions." Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1252424536/.
Повний текст джерелаGrisenti, David L. "The effect of bimolecular quenching reactions on energy transfer processes in oligometallic metal to ligand charge transfer excited states." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1495960661&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Повний текст джерелаHerman, Leslie. "Ru(II) under illumination: a study of charge and energy transfer elementary processes." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210399.
Повний текст джерелаL’ensemble de notre travail s’est concentré sur ces deux domaines d’applications. Par l’étude de différents processus de transfert de charges/d’énergie au sein des complexes seuls (processus intramoléculaires) ou en interaction avec un environnement spécifique (processus intermoléculaires), nous avons souhaité mettre en évidence l’intérêt de l’utilisation d’un nouveau ligand plan étendu, le tpac, au sein de complexes du Ru(II). Un tel ligand permet en effet de conférer d’une part une affinité élevée des complexes résultants pour l’ADN, et d’autre part, de par sa nature pontante, de connecter des unités métalliques entre elles au sein d’entités supramoléculaires de taille importante.
Les propriétés photophysiques de quatre complexes basés sur le ligand plan étendu tpac, le [Ru(phen)2tpac]2+ (P) et son homologue dinucléaire le [(phen)2Ru tpac Ru(phen)2]4+ (PP) (à base de ligands ancillaires phen), ainsi que le [Ru(tap)2tpac]2+ (T) et son homologue dinucléaire le [(tap)2Ru tpac Ru(tap)2]4+ (TT) (à base de ligands ancillaires tap), ont été étudiées et comparées entre elles.
L’examen de ces propriétés, d’abord pour les complexes seuls en solution, en parallèle avec celles de complexes dinucléaires contenant un ligand pontant PHEHAT, a permis de mettre en évidence l’importance de la nature du ligand pontant utilisé. Ces résultats ont ainsi révélé qu’un choix judicieux du ligand pontant permet de construire des entités de grande taille capables de transférer l’énergie lumineuse vers un centre (cas du ligand PHEHAT), ou, au contraire, de relier entre elles des entités ne s’influençant pas l’une l’autre d’un point de vue photophysique (cas du ligand tpac).
Les propriétés des complexes du tpac, étudiés cette fois en présence de matériel génétique (mononucléotide GMP, ADN ou polynucléotides synthétiques), se sont révélées très différentes selon que le complexe portait des ligands ancillaires phen (P, PP) ou tap (T, TT). Seuls les complexes à base de tap sont en effet photoréactifs envers les résidus guanine. Nous avons dès lors focalisé cette partie de notre travail sur les deux complexes T et TT. Cette photoréaction, ainsi que le transfert d’électron photoinduit entre ces complexes excités et la guanine, ont pu être mis en évidence par différentes techniques de spectroscopie d’émission tant stationnaire que résolue dans le temps, ainsi que par des mesures d’absorption transitoire dans des échelles de temps de la nano à la femto/picoseconde. L’étude du comportement photophysique des complexes en fonction du pH a en outre révélé de manière très intéressante que, pour des études en présence d’ADN, la protonation des états excités des complexes devait être considérée. Les résultats de cette étude nous ont fourni des pistes quant à l’attribution des processus observés en absorption transitoire.
Le transfert d’électron a également fait l’objet d’une étude par des méthodes théoriques. Ces calculs ab initio ont permis de mettre en évidence une faible influence de l’énergie de réorganisation sur la vitesse de transfert d’électron, qui semble dépendre plus sensiblement de la non-adiabaticité du processus, mais surtout de l’énergie libre de la réaction et d’un éventuel couplage à un transfert de proton.
L’ensemble des résultats obtenus avec les complexes T et TT en présence de matériel génétique, qui, de manière assez inattendue, sont très semblables, indiquent que ces complexes présentent tous deux un grand intérêt pour le développement de nouvelles drogues antitumorales photoactivables.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Cheng, Yuan-Chung Ph D. Massachusetts Institute of Technology. "Quantum dynamics in condensed phases : charge carrier mobility, decoherence, and excitation energy transfer." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34496.
Повний текст джерелаVita.
Includes bibliographical references.
In this thesis, we develop analytical models for quantum systems and perform theoretical investigations on several dynamical processes in condensed phases. First, we study charge-carrier mobilities in organic molecular crystals, and develop a microscopic theory that describes both the coherent band-like and incoherent hopping transport observed in organic crystals. We investigate the structures of polaron states using a variational scheme, and calculate both band-like and hopping mobilities at a broad range of parameters. Our mobility calculations in 1-D nearest-neighbor systems predict universal band-like to hopping transitions, in agreement with experiments. Second, motivated by recent developments in quantum computing with solid-state systems, we propose an effective Hamiltonian approach to describe quantum dissipation and decoherence. We then applied this method to study the effect of noise in a number of quantum algorithms and calculate noise threshold for fault-tolerant quantum error corrections (QEC). In addition, we perform a systematic investigation on several variables that can affect the efficiency of the fault-tolerant QEC scheme, aiming to generate a generic picture on how to search for optimal circuit design for real physical implementations.
(cont.) Third, we investigate the quantum coherence in the B800 ring of' of the purple bacterium Rps. acidophila and how it affects the dynamics of excitation energy transfer in a single LH2 complex. Our calculations suggest that the coherence in the B800 ring plays a significant role in both spectral and dynamical properties. Finally, we discussed the validity of Markovian master equations, and propose a concatenation scheme for applying Markovian master equations that absorbs the non-Markovian effects at short times in a natural manner. Applications of the concatenation scheme on the spin-boson problem show excellent agreements with the results obtained from the non-Markovian master equation at all parameter range studied.
by Yuan-Chung Cheng.
Ph.D.
Mutz, Niklas [Verfasser]. "Energy and Charge Transfer at Hybrid Interfaces Probed by Optical Spectroscopy / Niklas Mutz." Berlin : Humboldt-Universität zu Berlin, 2021. http://d-nb.info/1232726060/34.
Повний текст джерелаAcharya, Khem. "Excitation energy transfer and charge separation dynamics in photosystem II: hole-burning study." Diss., Kansas State University, 2012. http://hdl.handle.net/2097/13600.
Повний текст джерелаDepartment of Chemistry
Ryszard J. Jankowiak
The constituents of oxygen-evolving photosystem II core complexes—antenna proteins (CP43 and CP47) and reaction center (RC)—have been the subject of many studies over the years. However, the various issues related to electronic structure, including the origin/composition of the lowest-energy traps, origin of various emission bands, excitation energy transfer (EET), primary charge separation (CS) processes and pigment site energies remain yet to be fully resolved. Exploiting our state-of-the-art techniques such as low-T absorption, fluorescence, and hole burning (HB) spectroscopies, we resolved some of the issues particularly related to CP47 and isolated RC protein complexes. For example, we demonstrated that the fluorescence origin band maximum (~695 nm) originates from the lowest-energy state ~693 nm of intact CP47. In intact CP47 in contrast to destablished protein complexes, the band (~695 nm) does not shift in the temperature range of 5–77 K unless hole-burning takes place. We also studied a large number of isolated RC preparations from spinach, and wild-type Chlamydomonas reinhardtii (at different levels of intactness), as well as its mutant (D2-L209H), in which the active branch pheophytin (PheoD1) has been genetically replaced with chlorophyll a (Chl a). We showed that the Qx-/Qy-region site-energies of PheoD1 and PheoD2 are ~545/680 nm and ~541.5/670 nm, respectively, in good agreement with our previous assignment [Jankowiak et al. J. Phys. Chem. B 2002, 106, 8803]. Finally, we demonstrated that the primary electron donor in isolated algal RCs from C. reinhardtii (referred to as RC684) is PD1 and/or PD2 of the special Chl pair (analogous to PL and PM, the special BChl pair of the bacterial RC) and not ChlD1. However, the latter can also be the primary electron donor (minor pathway) in RC684 depending on the realization of the energetic disorder. We further demonstrate that transient HB spectra in RC684 are very similar to P+QA - PQA spectra measured in PSII core, providing the first evidence that RC684 represent intact isolated RC that also possesses the secondary electron acceptor, QA. In summary, a new insight into possible charge separation pathways in isolated PSII RCs has been provided.
Latimer, Darin Rae. "Determination of charge, atom, momentum and energy transfer rate coefficients near 5 K." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186873.
Повний текст джерелаBengtsson, Kristoffer. "C/O+ charge transfer & the Olson-Demkov model." Thesis, Uppsala universitet, Teoretisk astrofysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-453883.
Повний текст джерелаSupernovor är bland de mest extrema fenomen vi kan observera i hela Universum. Dessa våldsamma explosioner lämnar spår efter sig i många år och har varit ovärdeliga objekt att observera för att lära oss mer hur vår galax och Universum har utvecklats över tid. Ljuset från supernovor och deras kvarlevor kan analyseras för att ta reda på vad för ämnen som finns kvar eller som har bildats av både explosionen och de processer som ägt rum efteråt. En typ av reaktion som är viktig för att fullt ut förstå dessa miljöer är så kallade "laddningsöverföringar", en reaktion där en laddad och en oladdad partikel interagerar med varandra varvid laddningen förflyttas mellan de två. Detta projekt har fokuserat på en modell som avser att räkna ut uppskattningar på hur sannolikt det är för dessa reaktioner att äga rum. Modellen, som kallas för Olson-Demkov-modellen, har även jämförts med andra modeller för att se under vilka förhållanden som den fungerar.
Borgström, Magnus. "Controlling Charge and Energy Transfer Processes in Artificial Photosynthesis : From Picosecond to Millisecond Dynamics." Doctoral thesis, Uppsala University, Department of Physical Chemistry, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6017.
Повний текст джерелаThis thesis describes an interdisciplinary project, where the aim is to mimic the initial reactions in photosynthesis. In photosynthesis, the absorption of light is followed by the formation of charge-separated states. The energy stored in these charge-separated states is further used for the oxidation of water and reduction of carbon dioxide. In this thesis the photo-induced processes in a range of supramolecular complexes have been investigated with time resolved spectroscopic techniques. The complexes studied consist of three types of units; photosensitizers (P) capable of absorbing light, electron acceptors (A) that are easily reduced and electron donors (D) that are easily oxidised. Our results are important for the future design of artificial photosystems, where the goal is to produce hydrogen from light and water.
Two molecular triads with a D-P-A architecture are presented. In the first one, a photo-induced charge-separated state was formed in an unusually high yield (φ>90%). In the second triad, photo-irradiation led to the formation of an extremely long-lived charge-separated state (τ = 500 ms at 140K). This is also the first synthetically made triad containing a dinuclear manganese unit as electron donor.
Further, two sets of P-A dyads are presented. In both, the expected photo-induced reduction of the electron acceptor is diminished due to competing energy transfer to the triplet state of the acceptor.
Finally, a P-P-A complex containing two separate photosensitizers is described. The idea is to produce high-energy charge-separated states by using the energy from two photons.
Borgström, Magnus. "Controlling charge and energy transfer processes in artificial photosynthesis : from picosecond to millisecond dynamics /." Uppsala : Acta Universitatis Upsaliensis : Universitetsbiblioteket [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6017.
Повний текст джерелаShao, Shuai. "Synthesis and Studies of Wide-Band Capturing BODIPY-Fullerene Based Donor-Acceptor Systems." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1703394/.
Повний текст джерелаLim, Gary Lloyd Nogra. "Elucidation of Photoinduced Energy and Electron Transfer Mechanisms in Multimodular Artificial Photosynthetic Systems." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc984185/.
Повний текст джерелаBanjoko, Victor O. "Design, synthesis and spectroscopy of terpyridine materials: from energy and charge transfer to chemosensor applications." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2010. http://digitalcommons.auctr.edu/dissertations/168.
Повний текст джерелаLinderl, Theresa [Verfasser], and Wolfgang [Akademischer Betreuer] Brütting. "Charge Transfer States and Energy Losses in Organic Solar Cells / Theresa Linderl ; Betreuer: Wolfgang Brütting." Augsburg : Universität Augsburg, 2018. http://d-nb.info/1159880476/34.
Повний текст джерелаPruttivarasin, Thaned. "Study of low energy Ytterbium atom-ion charge transfer collisions using a surface-electrode trap." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45339.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 113-114).
We demonstrate a new isotope-selective system to measure low energy charge transfer collisions between ytterbium ions and atoms in the range of collisional energy from 2.2x 10-5 eV to 4.3x 10-3 eV, corresponding to effective temperature from 250 mK to 50 K. The charge transfer collisions are observed by spatially overlapping the 172yb+ ions in the surface-electrode trap and 174Yb atoms in the magneto-optical trap, and measuring ion loss. We confirm that, in the Langevin regime, the charge transfer collisional rate is independent of the collisional energy. The measured Langevin cross section is consistent with a theoretical value for the ytterbium atomic polarizability of 143 a.u., as calculated by Zhang and Dalgarno [1].
by Thaned Pruttivarasin.
S.B.
Rozsályi, Emese Tünde. "Theoretical study of charge transfer in ion-molecule collisions." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10152/document.
Повний текст джерелаCollisiosns of slow multiply charged ions with molecular species have been widely investigated in the past few years. Imortant experimental and theoretical effort has been focused on reactions with simple targets. Consideration of more complex molecular targets are now of increasing interest, in particular with regardto possible direect or indirect processes occuring in the irradiation of the biological medium.. In these reactions generally at relativity low energies, different processes have to be considered: exitation and fragmentation on the molecule, ionization of the gaseous target, and also possible charge transfer from the multicharged ion toward the biomolecule..Charge transfer can be investigated theoretically in the framework of the molecular representation of the collision. Such studies provides important information on the mecanism as well as on the electronic structure of the projectile and target during the reaction. The charge-transfer process in collisions on C2+ ions with hydrogen halide molecule (HF, HCI) has been studied by means of ab initio quantum chemistry molecular methods followed by semiclassical dynamical treatment in the keV collision energy range. The mechanism has been investigated in detail in each reaction, in connection with nonadiabatic interactions around avoided crodssings between states involved in the process
Steeger, Markus [Verfasser], Christoph [Gutachter] Lambert, and Tobias [Gutachter] Brixner. "Energy and Charge Transfer in Donor-Acceptor Substituted Hexaarylbenzenes / Markus Steeger. Gutachter: Christoph Lambert ; Tobias Brixner." Würzburg : Universität Würzburg, 2015. http://d-nb.info/1108781551/34.
Повний текст джерелаPaulus, Geraldine L. C. (Geraldine Laura Caroline). "Understanding and engineering interfacial charge transfer of carbon nanotubes and graphene for energy and sensing applications." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81686.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references.
Graphene is a one-atom thick planar monolayer of sp2 -bonded carbon atoms organized in a hexagonal crystal lattice. A single walled carbon nanotube (SWCNT) can be thought of as a graphene sheet rolled up into a seamless hollow cylinder with extremely high length-to-diameter ratio. Their large surface area, and exceptional optical, mechanical and electronic properties make these low-dimensional carbon materials ideal candidates for (opto-)electronic and sensing applications. In this thesis I studied the charge transfer processes that occur at their interface, and developed applications based on the discovered properties. When light is incident on a semiconducting SWCNT, it can excite an electron from the valence band to the conduction band, thereby creating a Coulombically bound electron-hole pair, also known as an exciton. Excitons can decay via radiative or non-radiative recombination or by colliding with other excitons. They can diffuse along the length of a SWCNT or hop from larger band gap SWCNTs to smaller band gap SWCNTs, a process known as exciton energy transfer (EET). We studied their behavior as a function of temperature in SWCNT fibers and showed that at room temperature the rate constant for EET is more than two orders of magnitude larger than that of each of the different recombination processes. This led us to construct a core-shell SWCNT fiber, which consists of a core of smaller band gap SWCNTs, surrounded by a shell of larger band gap SWCNTs, essentially forming what is known as a type I heterojunction. In agreement with a model that describes exciton behavior in the SWCNT fibers, we found that upon illumination all the energy (in the form of excitons) was quickly transferred from the shell to the core, faster than the excitons would otherwise recombine. The SWCNT fiber proved to be an efficient optical and energetic concentrator. We showed that SWCNTs and poly(3-hexylthiophene) (P3HT) form a type II heterojunction, which implies that excitons generated in the P3HT can easily dissociate into free charge carriers at the interface with the SWCNTs. Despite this, the efficiency of a P3HT/SWCNT bulk heterojunction (BHJ) photovoltaic is subpar. We developed a P3HT/SWCNT planar heterojunction (PHJ) and achieved efficiencies that were 30 times higher, which showed that the formation of bundled aggregates in BHJs was the cause: metallic SWCNTs can quench the excitons in an entire bundle. Another interesting feature of our SWCNT/P3HT PHJ is that a maximum efficiency was reached when -60 nm of P3HT was used, which is surprising since in a planar photovoltaic a maximum is expected for ~8.5 nm of P3HT, the value of the exciton diffusion length. A Kinetic Monte Carlo simulation revealed that bulk exciton dissociation was responsible for the lower efficiencies observed in devices with low P3HT thickness. Next we created and studied a junction between SWCNTs and a monolayer of graphene, an ideal one-dimensional/two-dimensional carbon interface. We used Raman spectroscopy to probe the degree of charge transfer at the interface and based on a shift in the G peak position of the graphene Raman signal at the junction deduced that a typical metallic (semiconducting) SWCNT dopes the graphene with 1.12 x 1013 cm-2 (0.325 x 101 cm-2) electrons upon contact, in agreement with the fact that the Fermi level of the SWCNTs is more shallow than that of the graphene. A molecular dynamics simulation ruled out that the observed Raman peak shifts are due to strain, although it did show that SWCNTs are being compressed radially by the graphene sheet, resulting in a widening of their Raman peaks. We studied charge transfer between diazonium molecules and graphene, to better inform transistor and sensor design. The reaction rate depends on the degree of overlap between the filled energy levels in graphene and the unoccupied ones in the diazonium molecule. We showed that with increasing degree of functionalization the charge transfer characteristics of a graphene field effect transistor (FET) alter in the following ways: the minimum conductivity decreases, the Dirac point upshifts, the conductivity plateau at high carrier density decreases and the electronhole conduction asymmetry increases. We developed a theoretical model of charge transport in graphene FETs that takes into account the effect of both short-range and long-range scatterers. Fitting it to the charge-transport data reveals quantitative information about the number of impurities in the substrate supporting the graphene, about the number of defects created as a result of the reaction, and about the degree of electron-hole conduction asymmetry. Graphene functionalization also affects the graphene Raman signal. After reaction, the D to G intensity ratio to increases, which is a sign of covalent modification of the graphene lattice. Additionally, the G peak and 2D peak positions increase while the 2D/G intensity ratio decreases, which are signs of hole-doping. Based on a Raman analysis, we were also able to show that the end group of the diazonium salt can affect both the degree of chemisorption (covalent modification) as well as the degree of physisorption (doping). Finally, we studied the effects of charge transfer between graphene and biological cells on the graphene Raman signal and designed a fundamentally new type of biosensor. Graphene can be thought of as a continuous array of information units (sensor units). The Raman signal collected in each unit can report on its local environment. In contrast to graphene FET biosensors, the graphene Raman biosensor offers subcellular spatial resolution. The graphene Raman signal was shown to display a strong dependence on pH. Metabolically active cells acidify their local environment; therefore, pH is a proxy for cellular metabolism. We placed both human embryonic kidney (HEK) cells that were genetically engineered to produce mouse antibodies and control HEK cells that were not genetically modified onto the graphene. Based on the change in the graphene Raman signal we deduced the former have a metabolic rate that is four times higher than that of the control cells. Increased cellular adhesion allows the cells to interact more closely with the graphene monolayer and intensifies the observed Raman effects.
by Geraldine L.C. Paulus.
Ph.D.
Harper, Theresa F. "I, Energy and charge transfer at nanocystalline Si interfaces ; II, reactions of porous Si with ketones /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9906493.
Повний текст джерелаJenkins, Judith Lynn. "Spectroscopic and Spectroelectrochemical Characterization of Fundamental Interfacial Charge Transfer Processes Relevant to Efficient Solar Energy Conversion." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/255173.
Повний текст джерелаGarrison, Shana A. "SYNTHESIS AND PHOTOPHYSICAL CHARACTERIZATION OF PORPHYRIN-CONTAINING SUPRAMOLECULAR SYSTEMS: STRUCTURAL ISSUES FOR PORPHYRIN PHOTOPHYSICS AND ELECTRON TRANSFER." Akron, OH : University of Akron, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1123616344.
Повний текст джерела"August, 2005." Title from electronic dissertation title page (viewed 09/24/2005). Advisor, David A. Modarelli; Committee members, Matthew Espe, Michael Taschner, Chrys Wesdemiotis, Stephanie Lopina; Department Chair, David Perry; Dean of the College, Charles B. Monroe; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
Ziemann, Dirk. "Theory of Excitation Energy Transfer in Nanohybrid Systems." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/22142.
Повний текст джерелаIn the following, transfer phenomena in nanohybrid systems are investigated theoretically. Such hybrid systems are promising candidates for novel optoelectronic devices and have attracted considerable interest. Despite a vast amount of experimental studies, only a small number of theoretical investigations exist so far. Furthermore, most of the theoretical work shows substantial limitations by either neglecting the atomistic details of the structure or drastically reducing the system size far below the typical device extension. The present thesis shows how existing theories can be improved. This thesis also expands previous theoretical investigations by developing models for four new and highly relevant nanohybrid systems. The first system is a spherical nanostructure consisting of an Au core and a CdS shell. By contrast, the second system resembles a finite nanointerface built up by a ZnO nanocrystal and a para-sexiphenyl aggregate. For the last two systems, a CdSe nanocrystal couples either to a pheophorbide-a molecule or to a tubular dye aggregate. In all of these systems, excitation energy transfer is an essential transfer mechanism and is, therefore, in the focus of this work. The considered hybrid systems consist of tens of thousands of atoms and, consequently, require an individual modeling of the constituents and their mutual coupling. For each material class, suitable methods are applied. The modeling of semiconductor nanocrystals is done by the tight-binding method, combined with a configuration interaction scheme. For the simulation of the molecular systems, the density functional theory is applied. T. Plehn performed the corresponding calculations. For the metal nanoparticle, a model based on quantized plasmon modes is utilized. As a consequence of these theories, excitation energy transfer calculations in hybrid systems are possible with unprecedented system size and complexity.
Abdelhameed, Mohammed. "Transfert de charge et d’énergie dans les dyades et oligomères de porphyrine." Mémoire, Université de Sherbrooke, 2014. http://savoirs.usherbrooke.ca/handle/11143/5360.
Повний текст джерелаHofmann-Mees, Dirk [Verfasser], and Stephan [Akademischer Betreuer] Kümmel. "Charge and excitation-energy transfer in time-dependent density functional theory / Dirk Hofmann-Mees. Betreuer: Stephan Kümmel." Bayreuth : Universität Bayreuth, 2013. http://d-nb.info/1059353652/34.
Повний текст джерелаKohlhoff, Mike. "Developing surface ionisation charge-transfer dynamics of hydrogen Rydberg atoms into an energy-resolved probe of surfaces." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:dd2cd7ea-689a-4707-88e3-0d5f0eb01e88.
Повний текст джерелаHan, Jie [Verfasser], and Andreas [Akademischer Betreuer] Dreuw. "A Quantum Chemical Look at Energy and Charge Transfer in N-Heteropolycycles / Jie Han ; Betreuer: Andreas Dreuw." Heidelberg : Universitätsbibliothek Heidelberg, 2020. http://d-nb.info/1210647729/34.
Повний текст джерелаAbrahams, Dhielnawaaz. "Charge Transfer and Capacitive Properties of Polyaniline/ Polyamide Thin Films." University of the Western Cape, 2018. http://hdl.handle.net/11394/6361.
Повний текст джерелаBlending polymers together offers researchers the ability to create novel materials that have a combination of desired properties of the individual polymers for a variety of functions as well as improving specific properties. The behaviour of the resulting blended polymer or blend is determined by the interactions between the two polymers. The resultant synergy from blending an intrinsically conducting polymer like polyaniline (PANI), is that it possesses the electrical, electronic, magnetic and optical properties of a metal while retaining the poor mechanical properties, solubility and processibility commonly associated with a conventional polymer. Aromatic polyamic acid has outstanding thermal, mechanical, electrical, and solvent resistance properties that can overcome the poor mechanical properties and instability of the conventional conducting polymers, such as polyaniline.
Glik, Elena A. "Spectroscopic Investigation of the Excited State Properties of Platinum(Ii) Charge Transfer Chromophores." Bowling Green, Ohio : Bowling Green State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=bgsu1256141493.
Повний текст джерелаWang, Jianren. "Nanostructured Redox-Active Mesoporous Silica Films Based on An Electron-Hopping Mechanism : Charge Transfer Behaviors And Energy Storage Potentials." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0216.
Повний текст джерелаA new type of silica-based energy storage materials operating with electron-hopping mechanism has been prepared by combining electrochemically-induced self-assembly method (EASA) and a copper-catalyzed azide-alkyne click (CuAAC) reaction. The redox active centers (ferrocene or cobaltocenium molecules) distributed on the surface of the silica film can directly commute electrons via the electron-hopping process. The results demonstrate this charge transfer mechanism is able to deliver a fast electron transfer rate even on the insulating silica substrate, resulting in a superior rate performance in comparison to the traditional faradic materials. The high density of redox molecules and the smooth counter ions diffusion pathway have been identified playing a pivotal role to ensure the fast electron-hopping process. Besides, the large-scale assembly of the electron-hopping system has been achieved by further generating the ferrocene functionalized silica film on a free-standing graphene foam electrode, exhibiting a 100-times higher capacity density, in comparison to that generating on ITO electrode, while maintaining the high rate performance. Finally, an attempt has been tried to assemble the graphene-supported ferrocene-functionalized silica into a flexible planar device, and the preliminary results has proved the feasibility of our proposed idea. Overall, in this thesis, the systematical study for the potential of the electron-hopping process in the energy storage field, which may pave a new way for the construction of energy storage materials
Unal, Ridvan. "Energy and charge state dependences of transfer ionization to single capture ratio for fast multiply charged ions on Helium /." Search for this dissertation online, 2001. http://wwwlib.umi.com/cr/ksu/main.
Повний текст джерелаForker, Roman. "Electronic Coupling Effects and Charge Transfer between Organic Molecules and Metal Surfaces." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-26163.
Повний текст джерелаZur Analyse der Struktur-Eigenschafts-Beziehungen dünner, epitaktischer Molekülfilme wird in situ differentielle Reflexionsspektroskopie (DRS) als Variante der optischen Absorptionsspektroskopie verwendet. Klare Zusammenhänge zwischen den Spektren und der unterschiedlich starken Kopplung zum jeweiligen Substrat werden gefunden. Während man breite und beinahe unstrukturierte Spektren für eine Quaterrylen (QT) Monolage auf Au(111) erhält, ist die spektrale Form von auf Graphit abgeschiedenem QT ähnlich der isolierter Moleküle. Durch Einfügen einer atomar dünnen organischen Zwischenschicht bestehend aus Hexa-peri-hexabenzocoronen (HBC) mit einem deutlich unterschiedlichen elektronischen Verhalten gelingt sogar eine effiziente elektronische Entkopplung vom darunter liegenden Au(111). Diese Ergebnisse werden durch systematische Variation der Metallsubstrate (Au, Ag und Al), welche von inert bis sehr reaktiv reichen, untermauert. Zu diesem Zweck wird 3,4,9,10-Perylentetracarbonsäuredianhydrid (PTCDA) gewählt, um Vergleichbarkeit der molekularen Filmstrukturen zu gewährleisten, und weil dessen elektronische Anordnung auf verschiedenen Metalloberflächen bereits eingehend untersucht worden ist. Wir weisen ionisiertes PTCDA an einigen dieser Grenzflächen nach und schlagen vor, dass der Ladungsübergang mit der elektronischen Niveauanpassung zusammenhängt, welche mit der Ausbildung von Grenzflächendipolen auf den entsprechenden Metallen einhergeht
Yu, Yongze Yu. "Interfacial Electron Transfer in p-Type Dye-Sensitized Nickel Oxide and Machine Learning for Energy Materials." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1564756409299145.
Повний текст джерелаMenting, Raoul Verfasser], Beate [Akademischer Betreuer] Röder, Oliver [Akademischer Betreuer] [Benson, and Christian [Akademischer Betreuer] Brückner. "Light-induced energy and charge transfer processes in artificial photosynthetic systems / Raoul Menting. Gutachter: Beate Röder ; Oliver Benson ; Christian Brückner." Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://d-nb.info/1030313601/34.
Повний текст джерелаMenting, Raoul Merijn [Verfasser], Beate Akademischer Betreuer] Röder, Oliver [Akademischer Betreuer] [Benson, and Christian [Akademischer Betreuer] Brückner. "Light-induced energy and charge transfer processes in artificial photosynthetic systems / Raoul Menting. Gutachter: Beate Röder ; Oliver Benson ; Christian Brückner." Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://nbn-resolving.de/urn:nbn:de:kobv:11-100206833.
Повний текст джерелаRatza, Viktor [Verfasser]. "Multi-stage Micropattern Gaseous Detectors for the ALICE TPC Upgrade - Studying and Modelling Charge Transfer and Energy Resolution / Viktor Ratza." Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1218301554/34.
Повний текст джерелаPlanells, Dillundé Miquel Angel. "Design and synthesis of organic sensitizers for dye solar cells: molecular structure vs device performance." Doctoral thesis, Universitat Rovira i Virgili, 2010. http://hdl.handle.net/10803/9054.
Повний текст джерелаThe present thesis focuses on the synthesis of organic chromophores as well as their use in optoelectronic devices, particulary in Dye Sensitized Solar Cells (DSSC). This kind of solar cell is based on a photoactive unit, a dye, anchored to a nanostructured metal-oxide semiconductor, usually TiO2, in a redox electrolyte media and sandwiched between two contact electrodes. In DSSC devices, each component (semiconductor, sensitizer and electrolyte) plays an important role in determining the final device efficiency, in a large part due to the charge transfer processes that take place at the TiO2/dye/electrolyte interface. Therefore, these charge transfer kinetics were studied using porphyrins, perylenes and donor - - acceptor organic dyes in order to understand and establish a relationship between the molecular structure and the device performance. Improved understanding of this relationship is crucial for improved molecular design of future dyes for DSSC.
Moberg, Simon. "Artificial photosynthesis - 4-Aminobenzoic acids effect on charge transfer in a photo catalytic system." Thesis, Uppsala universitet, Materialteori, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-390835.
Повний текст джерелаArtificiell fotosyntes används för att absorbera solenergi och förvara den i formen av kemiska bindningar. Systemet som används i denna studie gör detta genom att splittra vatten till vätgas och syrgas genom en plasmon assisterad process. Detta är ett förnyelsebart sätt att förvara energi och kan användas som ett alternativ till fossila bränslen. I denna studie studeras en liten del utav detta fotokatalytiska system nämligen interaktionen där plasmonaktiva silvernanopartiklar (Ag NPs) överför foto-exciterade elektroner genom molekyllänken 4-aminobensoesyra (pABA). Molekyllänken pABA överför laddning från silverytan till en halvledare och en katalys som utför splittringen av vattnet. pABA kan binda på olika sätt tillen silveryta och denna studie syftar till att undersöka vilken utav bindningarna som är starkast och vilken som effektivast överför laddning. För att göra detta simulerades tre system kvantmekaniskt med hjälp av en superdator, ett system för varje sorts bindning. Den totala fria energin av systemen beräknades och jämfördes. Av de tre undersökta bindningarna hadehollow-site bindningen (pABA som binder till tre silveratomer) längst energi, vilket betyder att det är den starkaste av bindningarna. Utöver detta så visade det sig att bandgapet (energin som krävs för att överföra laddning) minskade för pABA när den var bunden till Ag-ytan. Hollow-site bundet pABA hade även minst bandgap, vilket betyder att den kräver minst energi för att överföra laddning och är därmed den mest effektiva bindningen för det fotokatalytiska systemet.
Valenta, Christopher Ryan. "Microwave-energy harvesting at 5.8 GHz for passive devices." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52295.
Повний текст джерелаNano, Adela. "Towards optical memories : switchable optical systems for electron and energy transfer processes." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF011/document.
Повний текст джерелаThe present doctoral thesis work deals with the design, synthesis and characterization of organic and organometallic luminescent molecular frameworks for triggering Photoinduced electron Transfer (PeT) and Electronic Energy Transfer (EET) processes for applications in optical andelectronic devices. First, we turned toward the organic push-pull chromophores because they are useful model systems for studying the mechanism of PeT process. We synthesized new push-pull systems bearing a dicyanovinyl fragment as the electron-acceptor and a strong electron-donorsuch as julolidine and triazatruxene covalently linked through a BODIPY dye bridge. Electrochemical and photophysical studies showed a pronounced charge transfer character within the new push-pull systems. Furthermore, we synthesized and studied a series of chelating N^O-type ligands (Schiff base-type), based on the strong electron-donating julolidine motif, displaying ESIPT process. Their luminescence profiles exhibited panchromatic luminescence band covering the whole visible spectrum. Complexation of N^O-site with boron difluoride fragment suppressed the ESPIT process and highly increased the fluorescence quantum yield. The N^O-chelating ligands were combined with Pt(II) chromophore, B(III) and Ir(III) such as to obtainmultichromophoric frameworks. According to the photophysical studies, EET processes were observed within the multichromophoric systems. We successfully obtained a new florescent switching triad constructed around a photochromic core, [1,3]oxazine, which bears an energy-donor and an energy-acceptor module such as to directly control the EET process