Hydrocarbon sensing with thick and thin film p-type conducting perovskite materials

Abstract

The members of the p-type semiconducting SrTi 1−x Fe x O 3−δ family of perovskites have been studied as novel materials for hydrocarbon sensor applications. Screen-printed thick film devices are contrasted to thin films prepared by pulsed laser deposition (PLD). In order to enhance sensor specificity towards hydrocarbons, the influence of iron content, x, film thickness and operating temperature in the range from 300 to 500• C has been investigated. In addition, the use of a catalytically active cover layer made of a platinum-doped zeolite has been successfully studied to reduce the influence of species with cross-interference. An initial model explaining the underlying sensing mechanism is proposed.

Selectivity enhancement of p-type semiconducting hydrocarbon sensors—The use of sol-precipitated nano-powders

“…Fig. 4), the following sections focus on measurements at 400 • C, which had been identified previously as the optimum operating temperature [9].…”

“…In particular, the SrTi 1−x Fe x O 3−δ members with a moderate iron content (x = 0.1-0.2) show best performance [9,10].…”

Zeolite-based Materials for Gas Sensors

“…A cover layer made of platinum-doped zeolite with catalytica activity has been proven to have an effect for reducing the cross-interference influence of some species. An initial model for explaining the sensing mechanism was proposed [36]. In order to improve the selectivity of metal oxide sensors, zeolites modified with chromium were used to control the selectivity to alkanes based on shape and size effects [37].…”

Effect of grain boundaries on hydrocarbon sensing in Fe-doped p-type semiconducting perovskite SrTiO3 films

“…In a model proposed recently for p-type semiconductors, 20 the thin oxygen adsorption layer on the surface surrounding the grain-boundary layers acts as an electron trap. The electrons that are released as a result of the redox reaction diffuse towards the negative electrode and are trapped in the acceptor sites of the adsorbed oxygen near the grain boundaries.…”