Fabrication of Sm-Based Perovskite-Type Oxide Thin-Films and Gas Sensing Properties to Acetylene

Abstract

Sm-based perovskite-type oxide (SmMeO 3 : Me = Cr, Mn, Fe, Co) thin-films could be synthesized by a wet-chemical method using an acetylacetone-Poly(Vinyl Pyrrolidone) (PVP) polymeric precursor method at 750˚C. The perovskitetype oxide thin-films were tried to apply an acetylene gas sensor based on AC impedance spectroscopy. Among the oxides tested, SmFeO 3 thin-film sensor showed good sensor responses in which the AC impedance at 20 kHz was depending on acetylene gas concentration between 2 ppm and 80 ppm at 400˚C.

Improvement of Sensing Performance of Impedancemetric C2H2 Sensor Using SmFeO3 Thin-Films Prepared by a Polymer Precursor Method

“…The electrical state of a B-site metal ion on a perovskite-type oxide might affect sensor properties because the sensor used for Fe-based perovskite-type oxides has shown a good response differentially [ 16 ]. The sensor response in this study might tentatively have progressed via chemisorbing C 2 H 2 on an Fe 3+ site, as shown in Figure 12 .…”

“…The prepared precursor solutions were spin-coated on an alumina substrate with Au interdigitated electrodes at 4000 rpm, and finally sintered at 750 °C for 2 h in air. The spin-coating and sintering processes were repeated 3 times [ 16 ] to avoid making cracks.…”

“…Many research results of density functional theory of CO adsorption properties for Fe-based perovskite oxides have been reported, and this way of thinking could improve the sensor properties because the electron orbital state (HOMO–LUMO) of B-site metal of the BO 6 octahedral ion influences many chemical properties [13,14,15]. In fact, we have reported that the SmFeO 3 thin-film is the only sensor material to have high sensitivity and selectivity to C 2 H 2 among the prepared SmBO 3 (B=Cr, Mn, Fe, Co) thin-films [16,17]. Therefore, we are currently researching the response mechanism from a standpoint of HOMO–LUMO energy interaction between the oxide and C 2 H 2 .…”

Manipulating the ferroelectric polarization state of BaTiO3 thin films

“…There is currently a strong interest towards developing ferroelectric materials for various applications such as their use in multiferroics systems [1][2][3][4], photoelectrochemical cells (PEC) [5][6][7][8], and heat and gas sensors [9][10][11]. Ferroelectricity is a particular property of non-centrosymmetric materials exhibiting a spontaneous electrical polarization that can be reversed by the application of an external electric field.…”