Grain boundary blocking of ionic conductivity in nanocrystalline yttria-doped ceria thin films

摘要: Nanocrystalline YDC thin films with grain-sizes ranging from 38 to 93-nm were prepared using pulsed laser deposition followed by thermal annealing. Ionic conductivity decreased up four orders of magnitude as the grain size increased. Using energy-dispersive X-ray spectroscopy, we showed that counter-intuitive reduction in grain-size is likely due dopant and impurity segregation near grain-boundaries. Spectroscopic evidence suggests blocking effect defect more dominant on ionic than grain-sizes.