Novel application of Yttria Stabilized Zirconia as a substrate for thin film CIGS solar cells
Yttria Stabilized Zirconia [YSZ] has a number of qualities that make it attractive as a substrate for fabrication of thin film copper indium gallium diselenide [CIGS] solar cells: these include flexibility, a smooth surface, lack of impurities such as iron and the ability to scale to a roll-to-roll format. As an insulator, YSZ is compatible with monolithic processing and its high temperature capabilities enable high efficiency deposition temperature. Small area [0.41 cm2] CIGS solar cells were fabricated on a YSZ substrate yielding a 17.3% efficient device.
Flexible thin film ceramics for high temperature thermal sensing applications
Abstract Yttria Stabilized Zirconia ceramics have been widely used as protective boundary for high temperature environments and flame shields, intrinsic barrier to moisture, and are often considered for extreme environments. This class of materials has the ability to withstand temperatures up to 3000 °C, far exceeding the maximum temperature of operation for most other materials including polymers. Previously, the design of high performing functional materials involving ceramics was limited due to the bulkiness and lack of flexibility of ceramics. However, with the advent of ultra-thin flexible ceramics, it is possible to create thin layered structures that were not previously possible. In this study the authors investigate the potential of 40 μm thin flexible ceramic strips as flame shields for silica aerogels and polydimethylsiloxane phosphor composites. Results show that thermographic phosphors can be excited across multiple layers of YSZ strips, and, their emission characteristics can be accurately detected across multiple layers. Both decay characteristics and amplitude ratio methods were investigated. The YSZ strips provided thermal protection to both aerogels and elastomers. Embedded thermographic phosphor-based temperature measurements were feasible to a depth of at least 120 μm.
Investigation of Glass-Like Sol-Gel Coatings for Corrosion Protection of Stainless Steel Against Liquid and Gaseous Attack
Glass-like sol-gel coatings have been investigated as corrosion protective coatings on stainless steel. Magnesium- and borosilicate coatings with thickness of about 100–700 nm and methyl-modified SiO2 coatings with a thickness of about 2 μm were deposited on stainless steel plates by dip-coating. The coatings were densified between 400°C and 500°C in different atmospheres (N2, air) for 1 h. The corrosion protection against gaseous attack was investigated by accelerated corrosion tests, at 800°C in air for 1 h. A corrosion protection factor was calculated from the relation Fe/Fe2O3, determined by XRD on the surface of coated and uncoated samples. Methyl-modified SiO2 coatings showed a protection factor, which was 2 orders of magnitude higher than for the other coatings. Electrochemical investigations were performed on samples submerged in a NaCl solution for 200 h. The corrosion propagation, polarization resistance and impedance vector were measured. For accelerated corrosion tests, polarization intensity curves were determined for high potentials of up to 1 V. Again excellent results were obtained for the methyl-modified SiO2 coatings, which remained passive for 200 h. Results of the salt spray corrosion test, however, showed no corrosion protection by the sol-gel coatings. After 2000 h in the salt spray chamber the steel was corroded and the coatings peeled off. It is concluded that for the further development of these coatings an improved interfacial passivation will be required.