Gas sensing properties of nanocrystalline La_(0.75)Ba_(0.25)FeO_3 thick-film sensors

摘要

In the present work, La_(0.75)Ba_(0.25)FeO_3 thick films were fabricated by printing the paste (a mixture of La_(0.75)Ba_(0.25)FeO_3 powders and binder) on an alumina substrate pre-deposited with Ag electrodes. After the printing process, the thick films were annealed at various temperatures. When the La_(0.75)Ba_(0.25)FeO_3 powders were prepared through annealing at 800℃ for 3h, the optimal final annealing temperature was about 700 ℃ for the La_(0.75)Ba_(0.25)FeO_3 thick film to obtain a large sensing response. The gas sensing properties of La_(0.75)Ba_(0.25)FeO_3 thick-film sensors depended on the film thickness. The film with thickness of D = 50μm exhibited the largest response among the four thick films (D = 30, 50, 70, and 100μm). La_(0.75)Ba_(0.25)FeO_3 thick-film sensors could detect acetone and ethanol with very low concentrations (e.g., 5ppm).