Grain Boundary Blocking Effect in Yttria Stabilized Zirconia Thin Films Meike V.F. Schlupp a , H. Ma a , J. Martynczuk a , M. Prestat a , and L. J. Gauckler a a Nonmetallic Inorganic Materials, Department of Materials, ETH Zurich, Switzerland The cross-plane oxygen ion conductivity of yttria stabilized zirconia thin films prepared by aerosol assisted chemical vapor deposition is strongly influenced by the thin film microstructure. Thin films with highly textured columnar grains oriented parallel to the current direction exhibit significantly higher conductivity than thin films with randomly oriented nanocrystalline microstructure, where ionic transport proceeds through the numerous grain boundaries. The total conductivity of columnar AA-CVD thin films is consistent with literature values on oxygen ion conduction through chemically pure YSZ grains as determined for microcrystalline samples, while that of the nanocrystalline specimens is similar to corresponding specific grain boundary conductivities. Introduction The ionic conductivity of nanocrystalline yttria stabilized zirconia (YSZ) has been extensively discussed in literature (1, 2, and references therein). The grain boundaries of pure YSZ are found to be partially blocking to ionic transport, and the specific grain- boundary conductivity of stabilized zirconia is approximately two orders of magnitude lower than the grain conductivity. However, most data is based either on nanocrystalline bulk samples, or on thin films measured in in-plane geometry. In this study, we present a reliable procedure for electrical cross-plane measurements by impedance spectroscopy to determine the ionic conductivities of 8mol% Y 2 O 3 stabilized zirconia (8YSZ) thin films (250-500nm thickness) obtained by non-vacuum aerosol assisted chemical vapor deposition (AA-CVD). AA-CVD is an economical thin film deposition method based on the production of gaseous precursor molecules in a simple non-vacuum ultrasonic spray pyrolysis setup. Film growth proceeds from the gas phase resulting in smooth and homogeneous thin films over several square centimetres (3). Our results show that the microstructure strongly influences the conductivity of YSZ thin films. Experimental 8YSZ thin films were prepared from zirconium and yttrium 2,4-pentanedionate precursors dissolved in ethanol at a concentration of 0.025M or 0.005M using synthetic air as carrier gas. More details on the deposition procedure can be found elsewhere (3). YSZ depositions were conducted on single-crystal sapphire substrates coated with ~10nm tantalum as adhesion layer and ~100nm platinum as back electrode. Platinum top ECS Transactions, 45 (1) 189-192 (2012) 10.1149/1.3701308 ©The Electrochemical Society 189 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 129.132.210.88 Downloaded on 2016-12-27 to IP