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Proceedings Paper

Electron losses in nanostructured anatase using transient absorption spectroscopy
Author(s): Hans van't Spijker; Albert Goossens
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Paper Abstract

In order to elucidate electron migration in dye-sensitised nanoporous anatase TiO2, time-of-flight short-circuit photocurrents and transient absorption spectra between 500 and 2000 nm have been recorded. It is found that electrons in TiO2 dominate the transient absorption between 900 and 1100 nm, whereas at wavelengths longer than 1100 nm absorption by electrons in the SnO2:F substrate prevails. To facilitate a qualitative analysis, the absorption cross-sections of electrons in TiO2 and SnO2:F have been measured. Combining transient absorption and photocurrent response data, the time-resolved recombination loss can be determined. When the excitation density is below 33.5 (mu) J/cm2, on average less than one electron per nanoparticle is injected. Under this condition the IPCE equals unity. When higher excitation densities are applied, more than one electron per nanoparticle is injected, losses become significant, and the IPCE reduces to 40%. The time evolution of the recombination loss reveals that recombination primarily takes place with a few microseconds. One mechanism involves the recombination of electrons with dye cations, occurring in the first 20 ns after laser flash excitation.

Paper Details

Date Published: 21 February 2002
PDF: 8 pages
Proc. SPIE 4465, Organic Photovoltaics II, (21 February 2002); doi: 10.1117/12.456928
Show Author Affiliations
Hans van't Spijker, Delft Univ. of Technology (Netherlands)
Albert Goossens, Delft Univ. of Technology (Netherlands)

Published in SPIE Proceedings Vol. 4465:
Organic Photovoltaics II
Zakya H. Kafafi; Denis Fichou, Editor(s)

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