Photoluminescence of pure and mixed-phase nanocrystalline TiO2: Influence of solvent environment on inter- and intra-particle carrier transport

COLL 493

Fritz J. Knorr, fknorr@wsu.edu and Jeanne L. McHale, jmchale@wsu.edu. Department of Chemistry, Washington State University, PO Box 644630, Pullman, WA 99164-4630
Applications of nanocrystalline TiO2 particles in photocatalysis and solar energy conversion depend strongly on the phase, commonly, anatase or rutile. Mixed phase TiO2 is also frequently used and may result in improved photocatalytic properties owing to interphasial separation of electrons and holes. We present room-temperature photoluminescence spectra, arising from surface defects, of pure and mixed phase TiO2 as a function of contacting fluid. We find two distributions of trap states contribute to the visible luminescence of anatase, one of which is absent in mixed phase systems. In a mixed phase sample prepared by thermal treatment of an anatase film, intensity variations in the rutile and anatase emissions, in the near-IR and visible, respectively, reveal interphasial carrier transport to be a strong function of contacting solvent. The implications of these results for applications of nanocrystalline TiO2 for solar energy conversion and photocatalysis will be presented.
 

Interfacial Electron Transfer and Solar Energy Conversion: From Molecules to Nanomaterials
2:00 PM-5:00 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. 226, Oral

Division of Colloid & Surface Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008