title: Photoreduction of mesoporous In2O3: mechanistic model and utility in gas sensing.
abstract: A model is proposed for the drop in electronic resistance of n-type semiconducting indium oxide (In(2)O(3)) upon illumination with light (350 nm, 3.5 eV) as well as for the (light-enhanced) sensitivity of In(2)O(3) to oxidizing gases. Essential features of the model are photoreduction and a rate-limiting oxygen-diffusion step. Ordered, mesoporous In(2)O(3) with a high specific surface area serves as a versatile system for experimental studies. Analytical techniques comprise conductivity measurements under a controlled atmosphere (synthetic air, pure N(2)) and temperature-resolved in-situ Fourier transform infrared (FTIR) spectroscopy. IR measurements reveal that oxygen vacancies form a donor level 0.18 eV below the conduction band.
authors.affiliation: University of Paderborn, Faculty of Science, Department of Chemistry, Warburger Strasse 100, 33098 Paderborn, Germany. thorsten.wagner@upb.de
authors.forename: Thorsten
authors.initials: T
authors.lastname: Wagner
authors.forename: Claus-Dieter
authors.initials: CD
authors.lastname: Kohl
authors.forename: Sara
authors.initials: S
authors.lastname: Morandi
authors.forename: Cesare
authors.initials: C
authors.lastname: Malagù
authors.forename: Nicola
authors.initials: N
authors.lastname: Donato
authors.forename: Mariangela
authors.initials: M
authors.lastname: Latino
authors.forename: Giovanni
authors.initials: G
authors.lastname: Neri
authors.forename: Michael
authors.initials: M
authors.lastname: Tiemann