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sp-Carbon Incorporated Conductive Metal-Organic Framework as Photocathode for Photoelectrochemical Hydrogen GenerationLu, Yang, Zhong, Haixia, Li, Jian, Dominic, Anna Maria, Hu, Yiming, Gao, Zhen, Jiao, Yalong, Wu, Mingjian, Qi, Haoyuan, Huang, Chuanhui, Wayment, Lacey J., Kaiser, Ute, Spiecker, Erdmann, Weidinger, Inez M., Zhang, Wei, Feng, Xinliang, Dong, Renhao 04 June 2024 (has links)
Metal-organic frameworks (MOFs) have attracted increasing interest for broad applications in catalysis and gas separation due to their high porosity. However, the insulating feature and the limited active sites hindered MOFs as photocathode active materials for application in photoelectrocatalytic hydrogen generation. Herein, we develop a layered conductive two-dimensional conjugated MOF (2D c-MOF) comprising sp-carbon active sites based on arylene-ethynylene macrocycle ligand via CuO4 linking, named as Cu3HHAE2. This sp-carbon 2D c-MOF displays apparent semiconducting behavior and broad light absorption till the near-infrared band (1600 nm). Due to the abundant acetylene units, the Cu3HHAE2 could act as the first case of MOF photocathode for photoelectrochemical (PEC) hydrogen generation and presents a record hydrogen-evolution photocurrent density of ≈260 μA cm−2 at 0 V vs. reversible hydrogen electrode among the structurally-defined cocatalyst-free organic photocathodes.
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Eine sp-Kohlenstoffhaltige Leitfähige Metallorganische Gerüstverbindung als Photokathode für die Photoelektrochemische WasserstoffentwicklungLu, Yang, Zhong, Haixia, Li, Jian, Dominic, Anna Maria, Hu, Yiming, Gao, Zhen, Jiao, Yalong, Wu, Mingjian, Qi, Haoyuan, Huang, Chuanhui, Wayment, Lacey J., Kaiser, Ute, Spiecker, Erdmann, Weidinger, Inez M., Zhang, Wei, Feng, Xinliang, Dong, Renhao 11 June 2024 (has links)
Metallorganische Gerüstverbindungen (englisch metal–organic frameworks, MOFs) sind aufgrund ihrer hohen Porosität von großem Interesse für eine Vielzahl von Anwendungen in der Katalyse und Gastrennung. Eine begrenzte Anzahl an aktiven Zentren sowie das Verhalten als elektrischer Isolator machen den Einsatz von MOFs als aktives Photokathodenmaterial für die photoelektrokatalytische Wasserstoffproduktion allerdings nicht möglich. Wir berichten hiermit von der Entwicklung eines gestapelten, leitfähigen, zweidimensional-konjugierten MOFs (englisch 2D conjugated MOF, 2D c-MOF) welches aktive sp-Kohlenstoffzentren enthält. Der MOF Cu3HHAE2 basiert auf einem makrozyklischen Aryl-Alkin Liganden, welcher via CuO4 Einheiten verknüpft ist. Dieser sp-Kohlenstoff haltige 2D c-MOF zeigt Halbleitereigenschaften und eine breite Absorption bis in den nah-infraroten Bereich (1600 nm). Erstmalig kann dank der hohen Anzahl an Dreifachbindungen Cu3HHAE2 als MOF-Photokathode für die photoelektrochemische
(PEC) Wasserstoffentwicklung verwendet werden. Verglichen mit anderen strukturell definierten, co-Katalysator freien organischen Photokathoden, zeigt er eine Rekordphotostromdichte für die Wasserstoffentwicklung von ≈ 260 μAcm⁻ ² bei 0 V gegen die reversible Wasserstoffelektrode (englisch reversible hydrogen electrode RHE).
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Three-dimensional stress measurement technique based on electrical resistivity tomography / 電気比抵抗トモグラフィ-に基づく三次元応力計測技術Lu, Zirui 25 September 2023 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第24896号 / 工博第5176号 / 新制||工||1988(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)准教授 PIPATPONGSA Thirapong, 教授 肥後 陽介, 教授 岸田 潔, 教授 安原 英明 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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Maturação cortical e habilidades auditivas em usuários experientes de Vibrant Soundbridge: estudo eletrofisiológico e comportamental / Cortical maturation and auditory skills in experienced users of Vibrant Soundbridge: electrophysiological and behavioral studyPizarro, Luzia Maria Pozzobom Ventura 15 June 2018 (has links)
Introdução: A atresia congênita de orelha constitui uma deformidade presente ao nascimento, de prevalência unilateral, decorrente da alteração no desenvolvimento das estruturas das orelhas externa e média. Geralmente, provoca perda auditiva condutiva, e pode ser acompanhada por componente sensorioneural. Dentre as formas de tratamento disponíveis, encontra-se o implante de orelha média Vibrant Soundbridge (VSB), que tem se mostrado eficaz no tratamento deste tipo de alteração. A literatura mostra melhora nos limiares tonais e nos resultados dos testes de percepção auditiva da fala, realizados com o uso do processador de fala após a cirurgia. Considerando que os indivíduos com este tipo de malformação podem passar por um período de privação sensorial auditiva anterior à reabilitação, torna-se interessante avaliar o estágio maturacional das estruturas auditivas corticais e o processamento das informações auditivas em nível central, bem como, verificar o benefício da indicação do VSB unilateral em situação de escuta difícil. Não foram encontrados estudos que abordam este aspecto e o emprego dos potenciais evocados auditivos corticais (PEAC) e do P300 em usuários de VSB. Objetivo: Analisar o impacto da perda auditiva condutiva e mista nos PEAC e P300 em usuários de VSB unilateral, com atresia de orelha bilateral, e verificar as habilidades auditivas, em situação de escuta difícil, considerando a indicação do VSB unilateral. Casuística e método: Vinte indivíduos, divididos em dois grupos, pareados em idade, sexo e grau de escolaridade. G1: dez indivíduos com perda auditiva condutiva ou mista bilateral, usuários de VSB unilateral, atendidos na Instituição de realização da pesquisa. Todos fizeram uso de aparelhos auditivos convencionais antes do VSB. G2: Dez indivíduos normo-ouvintes. Realização de audiometria em campo livre com o uso do VSB (apenas o G1), avaliação das habilidades auditivas pelo Hearing in Noise Test, pesquisa dos componentes P1, N1, P2, N2 e P300, em campo calibrado. Resultados: A média dos limiares tonais nas frequências de 500 a 3000 Hz, de 20 a 36 dB NA, mostrou que o VSB possibilitou o acesso aos sons da fala. Não foi observada diferença estatisticamente significante entre os valores de latência dos PEAC e P300 entre os grupos. Foi observada diferença estatisticamente significante entre o limiar de reconhecimento de sentenças e a relação sinal/ruído entre os grupos, sendo os melhores resultados apresentados pelo G2. Conclusão: Indivíduos com atresia de orelha e perda auditiva condutiva ou mista bilateral, quando adequadamente reabilitados, podem atingir a maturação das vias auditivas centrais e o processamento da informação auditiva em nível cortical. As habilidades de reconhecimento auditivo, sem e com ruído competitivo, mostraram-se defasadas quanto à normalidade, apontando para a indicação do VSB bilateral / Introduction: Congenital aural atresia is a congenital deformity. It is unilaterally prevalent due to alterations in the development of the external and middle ear structures. Congenital aural atresia causes conductive hearing loss and can be accompanied by sensorineural component. Among the available forms of treatment is the middle ear implant, Vibrant Soundbridge (VSB), which has been shown to be effective in treating this type of alteration. The literature shows improvement in tonal thresholds and in the results of tests of auditory perception of speech that were performed using the speech processor after surgery. Individuals with this type of malformation often experience a period of auditory sensory deprivation prior to rehabilitation. Hence, it is important to evaluate the maturation stage of the cortical auditory structures, the processing of auditory information at the central level, and to verify the benefit of unilateral VSB in difficult listening situations. There are no previous data on this aspect and with the use of cortical auditory evoked potentials (CAEP) and event-related potential (P300) in users of VSB. Aim: To analyze the impact of conductive and mixed hearing loss on CAEP and P300 in unilateral VSB users with bilateral ear atresia. To verify the auditory abilities in a difficult listening situation considering the indication for unilateral VSB. Materials and methods: Twenty individuals were divided into two groups matched for age, sex, and educational level. G1 comprised ten individuals with bilateral conductive or mixed hearing loss and users of unilateral VSB, who visited the research institution. All subjects used conventional hearing aids prior to VSB. G2 comprised ten normal hearing individuals. Audiometry in the free field was performed with the use of VSB (G1 only) and evaluation of hearing skills by the Hearing in Noise Test was conducted; components P1, N1, P2, N2, and P300 in a calibrated field were recorded. Results: Evaluation of the mean tonal thresholds in the frequencies between 500 and 3000 Hz, from 20 to 36 dB HL, demonstrated that VSB allowed access to speech sounds. There was no statistically significant difference in the CAEP and P300 latency values between the two groups. A statistically significant difference was observed in the sentence recognition threshold and the signal-to-noise ratio between the groups, with best results presented by G2. Conclusion: Individuals with congenital aural atresia and bilateral conductive or mixed hearing loss may reach maturation of the central auditory pathway and achieve adequate processing of auditory information at the cortical level, when rehabilitated. The auditory recognition skills, with and without competitive noise, were shown to be out of phase with normality, indicating the need for a bilateral VSB
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Maturação cortical e habilidades auditivas em usuários experientes de Vibrant Soundbridge: estudo eletrofisiológico e comportamental / Cortical maturation and auditory skills in experienced users of Vibrant Soundbridge: electrophysiological and behavioral studyLuzia Maria Pozzobom Ventura Pizarro 15 June 2018 (has links)
Introdução: A atresia congênita de orelha constitui uma deformidade presente ao nascimento, de prevalência unilateral, decorrente da alteração no desenvolvimento das estruturas das orelhas externa e média. Geralmente, provoca perda auditiva condutiva, e pode ser acompanhada por componente sensorioneural. Dentre as formas de tratamento disponíveis, encontra-se o implante de orelha média Vibrant Soundbridge (VSB), que tem se mostrado eficaz no tratamento deste tipo de alteração. A literatura mostra melhora nos limiares tonais e nos resultados dos testes de percepção auditiva da fala, realizados com o uso do processador de fala após a cirurgia. Considerando que os indivíduos com este tipo de malformação podem passar por um período de privação sensorial auditiva anterior à reabilitação, torna-se interessante avaliar o estágio maturacional das estruturas auditivas corticais e o processamento das informações auditivas em nível central, bem como, verificar o benefício da indicação do VSB unilateral em situação de escuta difícil. Não foram encontrados estudos que abordam este aspecto e o emprego dos potenciais evocados auditivos corticais (PEAC) e do P300 em usuários de VSB. Objetivo: Analisar o impacto da perda auditiva condutiva e mista nos PEAC e P300 em usuários de VSB unilateral, com atresia de orelha bilateral, e verificar as habilidades auditivas, em situação de escuta difícil, considerando a indicação do VSB unilateral. Casuística e método: Vinte indivíduos, divididos em dois grupos, pareados em idade, sexo e grau de escolaridade. G1: dez indivíduos com perda auditiva condutiva ou mista bilateral, usuários de VSB unilateral, atendidos na Instituição de realização da pesquisa. Todos fizeram uso de aparelhos auditivos convencionais antes do VSB. G2: Dez indivíduos normo-ouvintes. Realização de audiometria em campo livre com o uso do VSB (apenas o G1), avaliação das habilidades auditivas pelo Hearing in Noise Test, pesquisa dos componentes P1, N1, P2, N2 e P300, em campo calibrado. Resultados: A média dos limiares tonais nas frequências de 500 a 3000 Hz, de 20 a 36 dB NA, mostrou que o VSB possibilitou o acesso aos sons da fala. Não foi observada diferença estatisticamente significante entre os valores de latência dos PEAC e P300 entre os grupos. Foi observada diferença estatisticamente significante entre o limiar de reconhecimento de sentenças e a relação sinal/ruído entre os grupos, sendo os melhores resultados apresentados pelo G2. Conclusão: Indivíduos com atresia de orelha e perda auditiva condutiva ou mista bilateral, quando adequadamente reabilitados, podem atingir a maturação das vias auditivas centrais e o processamento da informação auditiva em nível cortical. As habilidades de reconhecimento auditivo, sem e com ruído competitivo, mostraram-se defasadas quanto à normalidade, apontando para a indicação do VSB bilateral / Introduction: Congenital aural atresia is a congenital deformity. It is unilaterally prevalent due to alterations in the development of the external and middle ear structures. Congenital aural atresia causes conductive hearing loss and can be accompanied by sensorineural component. Among the available forms of treatment is the middle ear implant, Vibrant Soundbridge (VSB), which has been shown to be effective in treating this type of alteration. The literature shows improvement in tonal thresholds and in the results of tests of auditory perception of speech that were performed using the speech processor after surgery. Individuals with this type of malformation often experience a period of auditory sensory deprivation prior to rehabilitation. Hence, it is important to evaluate the maturation stage of the cortical auditory structures, the processing of auditory information at the central level, and to verify the benefit of unilateral VSB in difficult listening situations. There are no previous data on this aspect and with the use of cortical auditory evoked potentials (CAEP) and event-related potential (P300) in users of VSB. Aim: To analyze the impact of conductive and mixed hearing loss on CAEP and P300 in unilateral VSB users with bilateral ear atresia. To verify the auditory abilities in a difficult listening situation considering the indication for unilateral VSB. Materials and methods: Twenty individuals were divided into two groups matched for age, sex, and educational level. G1 comprised ten individuals with bilateral conductive or mixed hearing loss and users of unilateral VSB, who visited the research institution. All subjects used conventional hearing aids prior to VSB. G2 comprised ten normal hearing individuals. Audiometry in the free field was performed with the use of VSB (G1 only) and evaluation of hearing skills by the Hearing in Noise Test was conducted; components P1, N1, P2, N2, and P300 in a calibrated field were recorded. Results: Evaluation of the mean tonal thresholds in the frequencies between 500 and 3000 Hz, from 20 to 36 dB HL, demonstrated that VSB allowed access to speech sounds. There was no statistically significant difference in the CAEP and P300 latency values between the two groups. A statistically significant difference was observed in the sentence recognition threshold and the signal-to-noise ratio between the groups, with best results presented by G2. Conclusion: Individuals with congenital aural atresia and bilateral conductive or mixed hearing loss may reach maturation of the central auditory pathway and achieve adequate processing of auditory information at the cortical level, when rehabilitated. The auditory recognition skills, with and without competitive noise, were shown to be out of phase with normality, indicating the need for a bilateral VSB
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Komponenty na bázi vlnovodu integrovaného do textilu / Textile Integrated Waveguide ComponentsCupal, Miroslav January 2020 (has links)
Práce je zaměřena na výzkum struktur založených na vlnovodu integrovaném do textilu (TIW). Pozornost je věnována elektrické charakterizaci textilních materiálů (textilní substráty, nitě), které jsou využívány při implementaci antén, rekonfigurovatelných a aktivních obvodů integrovaných do textilu. Práce se zabývá návrhem vícevrstvých přechodů mezi mikropáskovým vedením na konvenčním substrátu a vedeními integrovanými do textilu. Dále je prezentován koncept přepínače integrovaného do textilu. Přepínač je řízen vodivými sloupky, které vytvářejí otevřenou či zavřenou stěnu prostřednictvím stejnosměrně ovládaných PIN diod. Na závěr je formulována metodika návrhu kruhově polarizovaných antén integrovaných do textilu, jež jsou určeny pro práci v ISM pásmech až do 24 GHz. Všechny postupy návrhu byly ověřeny simulacemi a měřeními reálných vzorků, které byly vyrobeny sítotiskem stříbrnou polymerovou pastou. Polovodičové komponenty byly k obvodům přilepeny vodivým stříbrným lepidlem. Komponenty vyrobené sítotiskem byly porovnávány s referenčními strukturami, které byly realizovány pomocí samolepicí měděné fólie.
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Die Rolle des Sauerstoffanteils in Titandioxid bei Tantal-Dotierung zur Verwendung als transparentes leitfähiges OxidNeubert, Marcel 29 February 2016 (has links) (PDF)
Im Fokus der vorliegenden Arbeit lag die Untersuchung polykristalliner TiO2:Ta-Schichten, hergestellt mittels Gleichstrom-Magnetron-Sputtern durch Verwendung reduzierter keramischer Targets und anschließender thermischer Nachbehandlung im Vakuum der zunächst nichtleitfähigen amorphen Precursorschichten. Es wurden die physikalischen Zusammenhänge, welche die strukturellen, elektrischen und optischen Eigenschaften der kristallinen TiO2:Ta-Schichten beeinflussen analysiert und dabei eine empfindliche Abhängigkeit vom Sauerstofffluss während der Abscheidung festgestellt. Es zeigte sich, dass die Verringerung der kinetischen Energie der Plasmateilchen beim Magnetron-Sputtern durch die Erhöhung des Gesamtdruckes vorteilhaft ist, um das Wachstum des gegenüber Rutil besser leitfähigen Anatas in Verbindung mit dem für niedrige Widerstände notwendigen Sauerstoffdefizit zu realisieren.
Bei einem Gesamtdruck von 2 Pa abgeschiedene polykristalline TiO2:Ta-Schichten haben einen spezifischen Widerstand von 1,5·10-3 Ωcm, eine hohe Ladungsträgermobilität (≈8 cm2V-1s-1) und einen geringen Extinktionskoeffizienten von 0,006.
Die Abhängigkeit des elektrischen Widerstandes vom Sauerstoffdefizit in der TiO2:Ta-Schicht wurde unter dem Gesichtspunkt der Ladungsträgeraktivierung sowie der Bildung von Ti-Fehlstellen diskutiert, welche vermutlich zur Kompensation und Lokalisierung von freien Elektronen beitragen.
Darüber hinaus wurde zur effizienteren Gestaltung der thermischen Nachbehandlung die konventionelle Vakuumtemperung erstmalig erfolgreich durch die Blitzlampentemperung ersetzt. / The work is focused on understanding the physical processes responsible for the modification of the structural, electrical and optical properties of polycrystalline TiO2:Ta films formed by vacuum annealing of initially not conductive amorphous films deposited by direct current magnetron sputtering. It is shown that the oxygen deficiency of amorphous and annealed TiO2:Ta films, respectively, is critical to achieve low resistivity and high optical transmittance of the crystalline films. Increasing the total pressure during magnetron sputter deposition is shown to be beneficial to achieve the desired oxygen deficient anatase growth, which is discussed in terms of energetic particle bombardment.
Polycrystalline anatase TiO2:Ta films of low electrical resistivity (1,5·10-3 Ωcm), high free electron mobility (≈8 cm2V-1s-1), and low extinction (0,006) are obtained in this way at a total pressure of 2 Pa. The dependence of the polycrystalline film electrical properties on the oxygen content is discussed in terms of Ta dopant electrical activation as well as transport limiting processes taking into account the formation of Ti-vacancies.
In addition, the conventional vacuum annealing has been successfully substituted by the flash lamp annealing in the millisecond range.
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RF überlagertes DC-Sputtern von transparenten leitfähigen Oxiden / RF superimposed DC sputtering of transparent conductive oxidesHeimke, Bruno 05 September 2013 (has links) (PDF)
Die vorliegende Dissertation befasst sich mit dem RF- überlagerten DC-Sputtern von Indiumzinnoxid und aluminiumdotierten Zinkoxid. Bei dem dafür entwickelten synchron gepulsten RF/DC-Verfahren werden die zu untersuchenden Materialien gleichzeitig mit Hilfe eines RF- und eines PulsDC-Generators gesputtert.
Ein wesentliches Resultat der Untersuchungen ist, dass durch RF- überlagertes DCSputtern Schichten abgeschieden werden können, die im Vergleich zum DC- bzw. PulsDC-Sputtern geringere spezifische Widerstände aufweisen. Dies ist auf eine Verringerung von Defekten in den abgeschiedenen Schichten zurückzuführen. Es konnte anhand der Untersuchungen gezeigt werden, dass fur die Abscheidung von Indiumzinnoxid und aluminiumdotiertem Zinkoxid die Substrattemperatur beim RF überlagerten DC-Sputtern gegenüber dem DC-Sputtern um bis zu 100°C verringert werden kann.
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Synthèse des matériaux électroactifs à base de thiophènes et de bipyrroles dissymétriquesTshibaka, Tshitundu 07 1900 (has links)
Ces travaux ont été réalisés en collaboration avec le groupe du professeur William Skene. / Le couplage des aldéhydes aryliques et des amines pour donner les azométhines est une alternative intéressante pour la synthèse des comonomères conjugués. Contrairement aux techniques de couplage classiques qui conduisent à des mélanges de produits, il est possible, par cette méthode, d’obtenir sélectivement des composés ciblés et dissymétriques tout en contrôlant la stœchiométrie des réactifs et les solvants.
Dans le cadre de nos recherches sur les matériaux fonctionnels ayant des propriétés électrochromiques améliorées, nous avons planifié de conjuguer des thiophènes et des bipyrroles dissymétriques par les liaisons azométhines. Tout d’abord des analogues des 4-méthoxy-2,2’-bipyrroles 1-2 (chapitre 2) et 3-6 (chapitre 3) ont été synthétisés par une voie générale à partir de 4-hydroxyproline et convertis ensuite en dialdéhydes 8-13 (chapitre 3) qui, à leur tour, ont subit des condensations avec différents aminothiophènes pour donner les azométhines conjugués 17-23 (chapitre 3). / The condensation of amine and aldehyde functional groups is an attractive strategy for the synthesis of conjugated, conductive polymers. Unlike conventional coupling techniques that give a mixture of products, selective product formation affording unsymmetric products is possible by controlling the reagent stoechiometry and solvents.
A series of such polymers 17-23 (chapter 3) were synthesized by the dehydration of aminothiophenes and a series of asymmetric bisaldehydes 8-13 (chapter 3) featuring an asymmetric 4-methoxy-2,2'-bipyrrole core. The latter was constructed by a general route from 4-hydroxyproline providing derivatives 1-2 (chapter 2) and 3-6 (chapter 3), which were diformylated in the last step to afford the bisaldehyde monomers 8-13 (chapter 3). In the search for functional materials, the electrochromic properties of polymers 17-23 (chapter 3) were evaluated.
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Étude de phénomènes de commutation de résistance de films minces de LixCoO2 / Study of resistive switching phenomena in LixCoO2 thin filmsMai, Van Huy 03 July 2014 (has links)
La mémoire Flash est célèbre dans le domaine des mémoires non volatiles ; elle est actuellement extrêmement utilisée pour le stockage des données numériques dans presque tous type d'appareil électronique nomade (ordinateur portable, téléphone mobile, tablette, …). Pour dépasser ses limites actuelles (densité d'informations, rapidité d'accès, endurance), un grand nombre de recherches se développent, explorant notamment le concept de mémoires résistives (Re-RAM), qui repose sur la commutation entre deux états de résistance (ou plus) via l'application d'une tension. Les mémoires Re-RAM dont la variation de résistance dépend de réactions électrochimiques sont potentiellement de bonnes candidates ; les mécanismes d'oxydo-réduction impliqués sont cependant souvent de type filamentaire, mettant notamment en jeu des migrations de cations d’éléments métalliques (provenant des électrodes), ou de lacunes d’oxygène. Ce caractère filamentaire rend difficilement atteignable la miniaturisation extrême, à l’échelle nanométrique.Dans ce but, une classe de matériaux complètement différente -utilisée dans le domaine du stockage d'énergie- est explorée. L’objectif de cette thèse est ainsi d’approfondir l’étude des phénomènes de commutation de résistance observés sur des films de LixCoO2. Nous caractérisons d'abord les propriétés structurales et électriques, à l'échelle nanométrique, de tels films déposés sur divers types de substrats. Nous cherchons ensuite à déterminer les mécanismes électrochimiques à l’origine des modifications : celles-ci vont en effet en sens inverse pour un même signe de tension, selon que l’on se trouve dans la configuration d’un contact nanométrique pointe AFM/film, ou dans la configuration d’un contact micrométrique électrode/film/électrode. Dans la première configuration nous déterminons les réactions électrochimiques impliquées. Dans la deuxième, nous proposons un mécanisme radicalement différent, corroboré par plusieurs résultats convergents. Enfin, nous exposons de premiers résultats prometteurs, relatifs à l’applicabilité potentielle de ces films aux mémoires Re-RAM, et au-delà, aux circuits neuromorphiques (états multiples de résistance – phénomènes d'additivité). / Flash memory has been famous in the field of non-volatile memory; currently it is extremely used for digital data storage in almost type of mobile electronic device (laptop, mobile phone, tablet ...). To overcome its current limitations (information density, access speed, endurance), a large number of research develop, especially exploring the concept of resistive memory (Re- RAM), which is based on switching between two resistance states (or more) via the application of a voltage.The Re-RAM whose resistance change depends on electrochemical reactions are potentially good candidates; the involved redox mechanisms are often, with particular cations migration of metal elements (between the electrodes), or oxygen deficiencies. This filamentary nature makes difficult to achieve extreme miniaturization at the nanoscale.For this purpose, a completely different class of materials - used in the field of energy storage - is explored. The objective of this thesis is thus to deepen the study of resistance switching phenomena observed in films LixCoO2. We first characterize the structural and electrical properties at the nanoscale, such films deposited on various types of substrates. We then seek to determine the electrochemical mechanisms underlying modification: they are in effect in reverse for the same sign of potential, as it is in the configuration of a contact nanoscale AFM tip / film, or in the configuration of a micrometer contact electrode / film / electrode. In the first configuration we determine the electrochemical reactions involved. In the second, we propose a radically different mechanism, supported by several converging results. Finally, we present promising first results regarding the potential applicability of these films to Re - RAM, and beyond, the neuromorphic circuits (multiple resistance states - additivity phenomena).
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