In this article, Al-doped ZnO thin films deposited by a one single-layer approach are studied. An aqueous precursor solution was prepared for the deposition of Al-doped ZnO thin film via ink-jet printing. The physical properties of the ink were studied in detail by rheology measurement and drop visualization. The wetting of the ink with the substrate was studied by the use of wetting envelopes. A single layer of the ink was deposited on the substrate and fully processed. The thin films were studied by X-ray diffraction, scanning electron microscopy, resistivity measurements, and optical transmission measurements. The optimal dopant concentration was set at 3 at.%, which resulted in thin films with a resistivity of 2.54 cΩ cm and an optical transmission larger than 90% over the visible range of the electromagnetic spectrum.dopant level % ¼ 100 Â

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Abstract:In this paper, the formation of ZrO 2 and yttria-stabilised-zirconia (YSZ) aqueous colloidal systems via microwave assisted hydrothermal synthesis is studied. Microwave synthesis allows a fast screening of the influence of different parameters such as time and temperature. The temperature varied from 140 °C up to 180 °C and the used reaction time varied from 5 min up to 1 h. The synthesised zirconia nanoparticles have a particle size of 50 nm confirmed by TEM. A 1 H NMR (nuclear magnetic resonance) study helped to understand the stabilization mechanism of the synthesised particles. By the addition of ytrrium ions into the zirconia colloidal solution, YSZ could be formed via an additional thermal treatment. Hereby, the samples are heated up to 400 °C for 1 h. YSZ colloidal solutions are synthesised by making use of complexing agents such as nitrilotriacetic acid, ethylenediaminetetraacetic acid and citric acid to control the hydrolysis and condensation of both ions to avoid non-stoichiometric phases. The ratio of Zr/Y in the particles is quantified by XRF. The amorphous structure of those particles necessitates an additional thermal treatment up to 600 °C during 1 h in order to obtain crystalline YSZ.

Zirconia and Yttrium stabilized zirconia are well-known ceramic materials. Scaling down the dimension of these ceramics can result in a faster sintering process at lower temperatures. Microwave synthesis of nano-structured particles is a very attractive synthesis route because of the short synthesis time and low reaction temperature. This allows a fast screening of the influence of different parameters such as time, temperature and pressure on the final size and crystal phase of the particles. In this study Zr and Zr/Y aqueous precursors are mixed with a variety of complexing agents or surfactants in different ratios. The reason is twofold: (1) we aim for a stable precursor solution which is established by lowering the free ion concentration and (2) we want to see the influence of the complexing agents on the growth of the particles and the formation of crystalline phases. Particle sizes of these particle vary from 40 -200 nm. The crystallinity is confirmed by X-ray diffraction. The stabilization of these particles and possible exchange of the ligands is examined with NMR measurements (1D -proton combined with 2D NOESY) and is compared with TGA-DTA analysis of the isolated particles.