Quantification of the effect of 4-tert-butylpyridine addition to I-/I-3(-) redox electrolytes in dye-sensitized nanostructured TiO2 solar cells
2006 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 26, 13144-13150 p.Article in journal (Refereed) Published
Addition of 4-tert-butylpyridine (4TBP) to redox electrolytes used in dye- sensitized TiO2 solar cells has a large effect on their performance. In an electrolyte containing 0.7 M LiI and 0.05 M I-2 in 3-methoxypropionitrile, addition of 0.5 M 4TBP gave an increase of the open-circuit potential of 260 mV. Using charge extraction and electron lifetime measurements, this increases could be attributed to a shift of the TiO2 band edge toward negative potentials (responsible for 60% of the voltage increase) and to an increase of the electron lifetime (40%). At a lower 4TBP concentration the shift of the band edge was similar, but the effect on the electron lifetime was less pronounced. The working mechanism of 4TBP can be summarized as follows: (1) 4TBP affects the surface charge of TiO2 by decreasing the amount of adsorbed protons and/or Li+ ions. ( 2) It decreases the recombination of electrons in TiO2 with triiodide in the electrolyte by preventing triiodide access to the TiO2 surface and/or by complexation with iodine in the electrolyte.
Place, publisher, year, edition, pages
2006. Vol. 110, no 26, 13144-13150 p.
nanocrystalline tio2, back-reaction, charge recombination, photovoltaic cells, raman-scattering, transport, films, photocurrent, spectroscopy, coadsorbent
IdentifiersURN: urn:nbn:se:kth:diva-15794DOI: 10.1021/jp0619641ISI: 000238645700050ScopusID: 2-s2.0-33746367127OAI: oai:DiVA.org:kth-15794DiVA: diva2:333836
QC 201005252010-08-052010-08-05Bibliographically approved