Photovoltage in nanocrystalline porous TiO2 - art. no. 075204

Citation
V. Duzhko et al., Photovoltage in nanocrystalline porous TiO2 - art. no. 075204, PHYS REV B, 6407(7), 2001, pp. 5204
Citations number
30
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B
ISSN journal
01631829 → ACNP
Volume
6407
Issue
7
Year of publication
2001
Database
ISI
SICI code
0163-1829(20010815)6407:7<5204:PINPT->2.0.ZU;2-D
Abstract
Transient and spectral photovoltage (PV) is investigated in nanocrystalline porous TiO2, which belongs to a class of materials with a very low electri cal conductivity, i.e., with a huge Maxwell relaxation time. The PV in such materials is caused by diffusion of excess charge carriers with different diffusion coefficients. Usually, the diffusion coefficient for electrons is larger than that for holes in porous TiO2. The PV transients are strongly retarded in time with respect to the exciting light pulse. The retardation of the photovoltage transients becomes stronger with decreasing size of the interconnected TiO2 nanoparticles and generation of defect states. The ban d gap of porous TiO2 (rutile, anatase) and the preferential formation of el ectron traps below the band gap are analyzed.