Original scientific paper
Transmission electron microscopy, x-ray diffraction and Raman scattering studies of nanophase TiO2
Aleksandra Turković
; Ruđer Bošković Institute, P. O. Box 1016, 10001 Zagreb, Croatia
Anđelka Tonejc
; Department of Physics, Faculty of Sciences, University of Zagreb, P. O. Box 162, 10001 Zagreb, Croatia
Stanko Popović
; Ruđer Bošković Institute, P. O. Box 1016, 10001 Zagreb, Croatia; Department of Physics, Faculty of Sciences, University of Zagreb, P. O. Box 162, 10001 Zagreb, Croatia
Pavo Dubček
; Ruđer Bošković Institute, P. O. Box 1016, 10001 Zagreb, Croatia
Mile Ivanda
; Ruđer Bošković Institute, P. O. Box 1016, 10001 Zagreb, Croatia
Svetozar Musić
; Ruđer Bošković Institute, P. O. Box 1016, 10001 Zagreb, Croatia
Marijan Gotić
; Ruđer Bošković Institute, P. O. Box 1016, 10001 Zagreb, Croatia
Abstract
Dye-sensitized solar cells differ from conventional semiconductor devices in that they separate the function of light absorption from charge-carrier transport. The device is based on a 10-mm-thick optically transparent film of titanium dioxide (TiO2) particles of a few nanometers in size, coated with a monolayer of charge-transfer dye to sensitize the film for light harvesting. In the present authors' review, the principal role of the TiO2 photoanode is emphasized by a detailed presentation of its characterization by different experimental methods, while the photoelectric responses of the cells, a work which is still in progress, are indicated in the references cited. Hydrolysis of Ti(IV)-isopropoxide in isopropanol by the addition of water is a suitable chemical reaction for the production of nanosized TiO2. The properties of nanosized TiO2 can be modified by the hydrolysis catalyst, pH of the solution, temperature, presence of complexing ligand and the colloidal state of TiO2 precursor. In the present work, the microstructural properties of nanosized TiO2 were studied by HREM, ED, XRD, SAXS and Raman spectroscopy. HREM was used to determine both grain and pore sizes. Electron diffraction and X-ray diffraction provided evidence of nanocrystalline anatase and brookite phases. The grain sizes of the anatase and brookite phases changed from (5±1) to (12±3) nm with an increase of the treating temperature up to 773 K, as shown by XRD. An method of determining nanosized TiO2 grain size based on low-frequency Raman scattering, is presented.
Keywords
Hrčak ID:
299844
URI
Publication date:
1.6.1997.
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