Preparation and gas sensing characteristics of nanoparticulate p-type semiconducting LnFeO3 and LnCrO3 materials

Nanoparticulate perovskite-type LnBO(3) (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tin, Yb, Lu; B = Cr, Fe) oxides are prepared by polyol-mediated synthesis. X-ray diffraction is used to confirm the structure of the materials, and scanning electron microscopy is applied to image the sample morphology. The powders are used for the preparation of suspensions that are deposited as thick films on comb-type Pt electrodes on alumina substrates. Electrical characterization is performed by using high-throughput impedance spectroscopy. The materials exhibit p-type semiconductor behavior, and their sensitivity towards H-2, CO, NO, NO2, and propylene in a temperature range from 200 to 500 degrees C is analyzed. In addition, the time-resolved response of the LnFeO(3) materials is investigated. A correlation between the Ln-O binding energy and the sensing properties is observed.