Estudo da Influência da Topografia na Difusão de Eletrólito em Filmes Finos de Titanato de Bário

Abstract

This work carried out the study of the electronic exchange between the potassium tri iodide electrolyte and thin films of Barium Titanate (BTO). The synthesis and deposi tion of BTO films on copper and FTO substrate were performed. The compound was synthesized by the Microwave-Assisted Hydrothermal method and deposited by the new deposition technique Dip-Electro-Coating (DEC). In the depositions of the BTO films, immersion times of 2min, 4min, 8min and 16min were used, with potential differences of 10V, 15V and 20V and with withdrawal velocity of 1mm/s. The powder was characterized chemically and the films topographically and electochemically. The composite was cha racterized by X-ray diffraction and the topography (area, thickness and roughness) of the BTO films was characterized by Scanning Electron Microscopy (SEM) and White-Light Interferometry (WLI). The electrochemical analysis of charge transport was performed by Cyclic Voltammetry (VC) and by Linear Scanning Voltammetry (VVL). The XRD characterization showed that the synthesis of the compound was successful with cubic phase. The deposition technique via DEC was successful in the deposition of BTO films on copper and FTO substrates. BTO thin films are uniformities, densities and roughnes ses. The characterization by Voltammetry was made in the BTO films, using triiodide potassium electrolyte, with an electrochemical cell of three electrodes. The BTO film was used as a working electrode. The voltammograms were obtained with scanning velocities of 0.005V/s, 0.01V/s, 0.015V/s and 0.02V/s, presenting only anode peaks of irreversible nature and showing good reproducibility. The current density varied quadratically with the scanning rate, according to the Delahay model, indicating the linear dependence of the current with the area for these films. Considering the scan speed of 0.01V/s, it was possible to observe that the current follows a power law in relation to the variation of thickness. This power decreases with increasing deposition rate, possibly due to variation of film porosity. This work then made possible the dominance of the deposition technique (DEC) and the understanding of how it influences the electronic transport through the topography of the thin films.