Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 71: Poster Session: Graphene / Topological Insulators / Interfaces and Surfaces

HL 71.30: Poster

Wednesday, March 28, 2012, 16:00–19:00, Poster D

The Change of Electrical Conductivity in Dependence of UV Illumination of Nano-Porous Titania (TiO₂) Combined with Infrared Spectroscopy (FTIR) — •Thomas Kriesche¹ and Thomas Bürgi² — ¹Phys.-Chem.-Institut, Im Neuenheimer Feld 253, 69120 Uni Heidelberg — ²Faculté des Sciences, Séction de Chimie, Département de Chimie Physique, Quai Ernest-Ansermet 30, CH-1211 Genève 4

The properties of nano-porous TiO₂ is widely investigated by FTIR. In particular this method is used to observe photocatalytic processes on TiO₂. The spectrometer IFS66v Bruker is expanded with an electro-meter (Keithley2100), which measures the electrical conductivity during IR-spectroscopy. Absorbed UV-light creates electrons and holes in the semiconductor, which recombine or can do reduction respectively oxidation of adsorbed molecules on surface. The conductivity is measured on top of a TiO₂ pill via a four point method, those is fixed in a Diffuse Reflectance IR (DRIFT) unit (PIKE EasiDiff). The well known degradation of malonic acid [1] has been studied with this setup. The recent work presents results from ATR-FTIR and DRIFT in MIR with the change of the electrical conductivity during UV illumination.

[1] I.Dolamic, T.Bürgi: Photoassisted Decomposition of Malonic Acid on TiO₂ Studied by in Situ Attenuated Total Reflection Infrared Spectroscopy, J. Phys. Chem. B 2006