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Thin films of mixed In/V oxides have been obtained by reactive RF sputtering. Their optical and electrochemical performances have been investigated in order to determine their possible applications in electrochromic devices as optically passive ion-storage layers. The targets used have been made of In 2 O 3 and V 2 O 5 powders mixed in different In/V ratios in a reactive sputtering atmosphere. Cyclic voltammetry and chronopotentiometry studies of these films have been performed. The films demonstrate high ion-storage capacity retained even after 1000 cycles without any significant degradation. Lithium diffusion coefficients, calculated by the potentiostatic intermittent titration technique (PITT), range around 10 -13 cm 2 s -1 . The optical measurements, taken in the UV-vis-NIR transmittance and reflectance modes, have demonstrated that films are electrochromic, but the presence of In enhances their transparency and optical passiveness. The photometric spectra evaluation by a computer fitting shows that the refractive index is lower for films with higher In content. This result is in good agreement with Rutherford backscattering spectroscopy (RBS) measurements. The material structure has been discussed on the basis of the above results, as a function of the measured thin film composition, and is corroborated by preliminary results of XPS surface analysis.

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Estudamos os efeitos de interface de filmes finos de eletrodos de V 2 O 5 sobre vidros com óxido de índio-estanho (ITO) para intercalação de Li utilizando combinações de métodos: perfil de profundidade por espectrometria de massas de íons secundários (SIMS), inserção-extração eletroquímica de íons lítio por voltametria cíclica de varredura lenta (SSCV) e por técnica de titulação potenciostática intermitente (PITT). Nós demonstramos que a distribuição de Li + no interior do filme de óxido é sempre distante de ser considerada homogênea e que diferentes etapas de difusão (paralelas às interfaces e bem como perpendiculares a elas) são consideradas por conter áreas de alguns cm 2 em experimentos com eletrodos. A margem exposta pelo corte da placa de vidro revestida com ITO e recoberta com V 2 O 5 desempenha um papel importante no processo, pelo fato de expor a interface V 2 O 5 -ITO ao eletrólito.We studied interface effects of thin film V 2 O 5 electrodes on top of indium tin oxide (ITO) glass for Li intercalation by means of a combination of methods: depth-profiling by secondary ion mass spectroscopy (SIMS), electrochemical insertion-extraction of lithium ions by slow-scan cyclic voltammetry (SSCV) and by potentiostatic intermittent titration technique (PITT). We show that the Li + distribution inside the oxide film is always far from homogeneous, and that different diffusion paths (parallel to interfaces as well as perpendicular to them) have to be considered in experiments with electrodes having areas of few cm 2 . The exposed edge formed when cutting out coupons from the coated glass plate supporting the V 2 O 5 electrode plays a significant role in the process, because it exposes the V 2 O 5 -ITO interface to the electrolyte.

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In this work, we studied radio-frequency reactively sputtered molybdenum oxide thin films. Thin films with distinct stoichiometries were obtained by varying the oxygen flow and maintaining all other deposition parameters constant. The relationship between optical, electrochemical, and mechanical behavior of the films submitted to lithium intercalation in an aprotic electrolyte is reported. Films deposited at low oxygen flow (B-films) are substoichiometric molybdenum oxide, with composition MoO3_ (0 < x c 1). Films deposited at high oxygen flow (T-films) approach the MoO, stoichiometry. B-films have a greater concentration of optically active sites and a more open structure when compared to T-films.