Dye-sensitized TiO{sub 2} solar cells: Structural and photoelectrochemical characterization of nanocrystalline electrodes formed from the hydrolysis of TiCl{sub 4}
- National Renewable Energy Lab., Golden, CO (United States)
The structure and photoelectrochemical properties of TiO{sub 2} films deposited onto SnO{sub 2} conducting glass from the ambient hydrolysis of TiCl{sub 4} and annealed at temperatures ranging from 100 to 500 C were studied by Raman spectroscopy. X-ray diffraction (XRD), transmission electron microscopy (TEM), intensity-modulated photovoltage spectroscopy (IMVS), and intensity-modulated photocurrent spectroscopy (IMPS) measurements. Analysis of the XRD and Raman spectra shows that TiCl{sub 4}-produced TiO{sub 2} films consist of rod-shaped particles that grow with an increasing annealing temperature. The AM-1.5 short-circuit photocurrent J{sub sc} and open-circuit photovoltage V{sub oc} of Ru[LL{prime}(NCS){sub 2}]-sensitized (L = 2,2{prime}-bypyridyl-4,4{prime}-dicarboxylic acid, L{prime} = 2,2{prime}-bipyridyl-4,4-ditetrabutylammoniumcarboxylate) 4.5 {micro}m thick rutile films increase significantly with annealing temperature, from 1.1 mA/cm{sup 2} and 602 mV at 100 C to 8.7 mA/cm{sup 2} and 670 mV at 500 C. Studies of the incident photon-to-current conversion efficiency (IPCE), the photocurrent-voltage characteristics, the optical appearance, the water content, and the particle size of the films indicate that the increase of both J{sub sc} and V{sub oc} with annealing temperature is due, in part, to increased dye adsorption resulting from the evaporation of surface water and the improved light-scattering properties of the film associated with the growth of rutile particles. Raman and XRD measurements and other observations indicate that treating transparent nanocrystalline anatase TiO{sub 2} electrodes with TiCl{sub 4} produces a translucent overlayer of rutile TiO{sub 2}. The increased film thickness and light-scattering characteristics of the rutile overlayer may explain, in part, the improved IPCE observed for dye-sensitized TiCl{sub 4}-treated nanocrystalline anatase TiO{sub 2} electrodes.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 351578
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 17 Vol. 103; ISSN 1089-5647; ISSN JPCBFK
- Country of Publication:
- United States
- Language:
- English
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