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Effects of doping by aluminum or lanthanum on the electrical and electroluminescence properties of Ca0.6Sr0.4TiO3:Pr thin films
摘要： Thin-film electroluminescent devices containing Ca0.6Sr0.4TiO3:Pr, Al-doped Ca0.6Sr0.4TiO3:Pr, or La-doped Ca0.6Sr0.4TiO3:Pr phosphors were prepared by a conventional sol–gel and firing method. Doping by Al improved the performance of the device markedly, in that its current-starting voltage and emission-starting voltage decreased, its luminance response became more rapid, and its relative quantum efficiency increased. Almost all the effects of doping with La were opposite to those of doping with Al. On stacking thin films of Al-doped Ca0.6Sr0.4TiO3:Pr and La-doped Ca0.6Sr0.4TiO3:Pr, the current-starting voltage and the emission-starting voltages decreased further and the relative quantum efficiency increased further in comparison with the Al-doped film. The effects of doping by Al and La can be understood by assuming that Ca0.6Sr0.4TiO3:Pr separates into n-type and p-type semiconducting regions as a result of the electromigration of oxygen vacancies, and that the oxygen-vacancy density increases or decreases on doping by Al and La, respectively.
关键词： Perovskite titanate,Praseodymium,Lanthanum,Oxide thin film,Aluminum,Electroluminescence
更新于2025-09-04 15:30:14
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Electro-morphological, structural, thermal and ionic conduction properties of Gd/Pr co-doped ceria electrolytes exhibiting mixed Pr3+/Pr4+ cations
摘要： Gd0.2-xPrxCe0.8O1.90, (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) has been synthesized by means of a simple co-precipitation route based on ammonium carbonate as the precipitating agent. The as-synthesized precursors are cerium-gadolinium-praseodymium amorphous hydroxycarbonates, which are nanometric in size with highly homogeneous morphology, leading to reactive doped and co-doped nanocrystalline (≈13 nm) ceria after a mild thermal treatment (2 h at 600 °C). The obtained results highlight the very positive effect of Pr on the powders’ sintering behaviour, which favour a better densification of the final pellets, thus improving both their microstructure (with relative densities of 97–99% after sintering at 1250 °C for 3 h) and electrochemical properties (up to 1.25?10–1 S cm?1 at 800 °C for sample 6Pr) compared to the state-of-art ceria-based electrolytes. Through a comprehensive characterization, a relation was formed between the Pr content and the microstructural features of the sintered pellets and their electrical behaviour. The amount of Pr doping was investigated over a wide range and 6 mol% has been established to be optimal (possessing the lowest electronic conductivity contribution). Definitely, these results indicate that Gd0.2-xPrxCe0.8O1.90 has an excellent set of characteristics, both microstructural and electrical, and a convenient fabrication process, thus making it perfectly suitable for IT-SOFC practical applications.
关键词： Ceria-based electrolyte,IT-SOFC,Co-precipitation,Praseodymium,Nanocrystalline ceria
更新于2025-09-04 15:30:14