Orientador: Fernando Alvarez / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-24T01:43:09Z (GMT). No. of bitstreams: 1 Scoca_DiegoLeonardoSilva_M.pdf: 4961271 bytes, checksum: 2f6307ff4adda022c6df4b03d2014fdd (MD5) Previous issue date: 2013 / Resumo: Neste trabalho foi investigada a influência do ambiente químico na fotoluminescência de filmes finos de Oxi-nitreto de titânio dopados com érbio (TiNxOy : Er). Os filmes finos foram crescidos utilizando a técnica de Deposição por Feixe de Íons (IBD ¿ Ion Beam Deposition) e, a fim de modificar o ambiente químico ao qual os íons de Er3+ estão submetidos para controlar as características da fotoluminescência dos íons de érbio, foi realizado tratamento térmico sequencial sob atmosfera de oxigênio, durante 30 minutos em cada uma das seguintes temperaturas: 250°C, 500°C, 750°C e 1000°C. A investigação do estado atômico e da concentração relativa de cada elemento presente nos filmes foi analisada através da técnica de XPS, para as amostras antes (AD) de passarem pelo tratamento térmico e após todos os tratamentos serem realizados (TA). A estrutura cristalina dos filmes foi investigada por Difração de Raio-X à Baixo Ângulo (1°) antes (AD) e após (TA) o tratamento térmico, enquanto que, através de espectroscopia Raman, foi acompanhada cada etapa (temperatura) do tratamento térmico, possibilitando a identificação de duas fases distintas do TiO2, onde a 750°C foram detectados modos vibracionais referentes a fase anatásio e, a 1000°C, modos vibracionais relacionados a fase rutilo. Os resultados de XRD à Baixo Ângulo após o tratamento térmico corroboram com os resultados obtidos por espectroscopia Raman a mesma temperatura. As propriedades de fotoluminescência (PL) dos filmes estudados também foram investigadas em cada etapa do tratamento térmico, evidenciando a influência deste tratamento na fotoluminescência dos filmes. Vale ressaltar a influência do nitrogênio inicial, que por estar em diferentes concentrações em cada amostra, favoreceu diferentes ambientes químicos em função do tratamento térmico, que modificou notadamente as características de fotoluminescência das amostras. Também foi possível notar a influência das fases cristalinas do TiO2 na PL dos filmes, pois esta apresentou uma emissão estreita em ~ 550nm para os filmes estudados quando estes se cristalizaram na fase anatásio, comportamento inexistente quando os filmes se recristalizaram na fase rutilo do TiO2. Medidas de PL em função da temperatura também foram realizadas, de forma que o quenching das emissões na região verde do espectro eletromagnético pôde ser observado, fornecendo uma estimativa para a diferença entre os níveis 2H11/2 e 4S3/2 dê ~ 93 meV (750 cm-1), concordando bem com a separação teórica calculada entre esses níveis. Portanto, neste trabalho foram observadas cinco emissões dos íons trivalente de vi érbio, com comprimentos de onda ~525nm, ~ 550nm, ~ 680nm, ~ 980nm e ~ 1540nm referentes as respectivas transições 2H11/2 -> 4 I15/2, 4S3/2 -> 4 I15/2, 4F9/2 -> 4 I15/2, 4I11/2 -> 4 I15/2 e 4I13/2 -> 4 I15/2, sendo que a característica das emissões no visível foram controladas a partir da concentração inicial de nitrogênio e da temperatura do tratamento térmico / Abstract: In this work was investigated the influence of chemical environment on photoluminescence of Erbium doped Titanium Oxi-Nitride thin films (TiNxOy : Er). The thin films were grown by Ion Beam Deposition technique and, in order to study the influence of the chemical environment which Er3+ ions are subjected, was performed a sequential thermal annealing in an oxygen atmosphere, during 30 minutes in each of the following temperatures: 250°C, 500°C, 750°C e 1000°C. The investigation of binding state and the relative concentration of each element in the films was analyzed by XPS technique for samples "as deposited¿ (AD) and after the ¿thermal annealing¿ (TA). The crystalline structure of the films was investigated by X-Ray Diffraction at Small Angle before (AD) and after thermal annealing (TA), while using Raman spectroscopy, each step of the thermal annealing was monitored. With this procedure was possible to identify two distinct phases of TiO2, with vibrational modes emerging at the annealing temperature of 750°C referring to anatásio phase and, annealing temperature of 1000°C associated with rutile. The results of XRD at Small Angle after thermal annealing corroborate the Raman spectra obtained at the same temperature. The properties of photoluminescence (PL) of the studied films were investigated in each stage of thermal annealing, showing the influence of this treatment on photoluminescence of the films. It is worth mentioning the influence of initial nitrogen that, being in different concentrations in each sample, favored different chemical environments after the annealing procedure, which markedly changed the characteristics of photoluminescence of the samples. It was also noted the influence of the crystalline phases of TiO2 in the PL of the films, by displaying a narrow emission at ~ 550nm when the thin film crystallized into anatásio phase, behavior absent when the recrystallization of the films took place in the rutile phase TiO2. PL measurements as a function of temperature also were performed, so the quenching of emission in the green region of electromagnetic spectrum can be observed. These experiments provide an estimate of the difference between the levels 2H11=2 and 4S3/2 of ~ 93 meV (750 cm-1), results that agree fairly well with the calculated theoretical separation between these levels. Therefore, in this work were observed five emissions of trivalent erbium ions, with wavelenghts ~ 525nm, ~ 550nm, ~ 680nm, ~ 980nm and ~ 1540nm regarding their transitions 2H11/2 -> 4 I15/2, 4S3/2 -> 4 I15/2, 4F9/2 -> 4 I15/2, 4I11/2 -> 4 I15/2 e 4I13/2 -> 4 I15/2, with characteristic of the visible emissions were monitored from the initial concentration of nitrogen and the annealing temperature / Mestrado / Física / Mestre em Física

Ein viel diskutiertes Thema unserer Zeit ist die Zukunft der Energiegewinnung und Speicherung. Dabei nimmt die Nanowissenschaft eine bedeutende Rolle ein; sie führt zu einer Effizienzsteigerung bei der Speicherung und Gewinnung durch bereits bekannte Materialien und durch neue Materialien. In diesem Zusammenhang ist die Chemie Wegbereiter für Nanomaterialien. Allerdings führen bisher die meisten bekannten Synthesen von Nanopartikeln zu undefinierten Partikeln. Eine einfache, kostengünstige und sichere Synthese würde die Möglichkeit einer breiten Anwendung und Skalierbarkeit bieten. In dieser Arbeit soll daher die Darstellung der einfachen Synthese von Mangannitrid-, Aluminiumnitrid-, Lithiummangansilicat-, Zirkonium-oxinitrid- und Mangancarbonatnanopartikel betrachtet werden. Dabei werden die sogenannte Harnstoff-Glas-Route als eine Festphasensynthese und die Solvothermalsynthese als typische Flüssigphasensynthese eingesetzt. Beide Synthesewege führen zu definierten Partikelgrößen und interessanten Morphologien und ermöglichen eine Einflussnahme auf die Produkte. Im Falle der Synthese der Mangannitridnanopartikel mithilfe der Harnstoff-Glas-Route führt diese zu Nanopartikeln mit Kern-Hülle-Struktur, deren Einsatz als Konversionsmaterial erstmalig vorgestellt wird. Mit dem Ziel einer leichteren Anwendung von Nanopartikeln wird eine einfache Beschichtung von Oberflächen mit Nanopartikeln mithilfe der Rotationsbeschichtung beschrieben. Es entstand ein Gemisch aus MnN0,43/MnO-Nanopartikeln, eingebettet in einem Kohlenstofffilm, dessen Untersuchung als Konversionsmaterial hohe spezifische Kapazitäten (811 mAh/g) zeigt, die die von dem konventionellen Anodenmaterial Graphit (372 mAh/g) übersteigt. Neben der Synthese des Anodenmaterials wurde ebenfalls die des Kathodenmaterials Li2MnSiO4-Nanopartikeln mithilfe der Harnstoff-Glas-Route vorgestellt. Mithilfe der Synthese von Zirkoniumoxinitridnanopartikeln Zr2ON2 kann eine einfache Einflussnahme auf das gewünschte Produkt durch die Variation derReaktionsbedingungen, wie Harnstoffmenge oder Reaktionstemperatur, bei der Harnstoff-Glas-Route demonstriert werden. Der Zusatz von kleinsten Mengen an Ammoniumchlorid vermeidet, dass sich Kohlenstoff im Endprodukt bildet und führt so zu gelben Zr2ON2-Nanopartikeln mit einer Größe d = 8 nm, die Halbleitereigen-schaften besitzen. Die Synthese von Aluminiumnitridnanopartikeln führt zu kristallinen Nanopartikeln, die in eine amorphe Matrix eingebettet sind. Die Solvothermalsynthese von Mangancarbonatnanopartikel lässt neue Morphologien in Form von Nanostäbchen entstehen, die zu schuppenartigen sphärischen Überstrukturen agglomeriert sind. / The development of new methods toward alternative clean energy production and efficient energy storage is a hot topic nowadays. In this context nanoscience has an important role to find suitable ways of increasing the efficiency of storage and production of energy of already known materials and new materials. However, until now the most well-known syntheses of MnN0,43 and Zr2ON2 nanoparticles lead to undefined particles. A simple, cheap and safe synthesis would offer the possibility of broader applications and scalability. We herein present the so-called urea-glass route which is used as a sol-gel process. This synthetic route leads to well-defined particle sizes, novel particle morphologies and allows the tailoring of the desired products. In the case of the synthesis of manganese nitride nanoparticles (MnN0,43), nanoparticles with a core-shell structure are obtained, their use as conversion materials in batteries is first introduced. On the other hand, the formation of zirconium oxynitride nanoparticles (Zr2ON2) can be easily influenced by varying the reaction conditions such as the amount of urea or the reaction temperature. The addition of small amounts of salt prevents the formation of carbon in the final product, leading to yellow Zr2ON2 nanoparticles with a size of d = 8 nm which show semiconductor behavior.