Direct measurement of the temperature coefficient of the electron quasi-Fermi level in dye-sensitized nanocrystalline solar cells using a titanium sensor electrode

K Lobato, L M Peter

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Abstract

A novel type of dye-sensitized cell (DSC) with a passivated titanium sensor electrode located on top of the nanocrystalline titanium dioxide layer has been used to study the temperature dependence of the electron quasi-Fermi level relative to the I-3(-)/I- redox-Fermi level under short circuit conditions. The results show that the Fermi level decreases with increasing temperature (-1.76 meV K-1) as predicted for diffusive electron transport at short circuit. A smaller temperature dependence (-0.25 meV K-1) of the position of the TiO2 conduction band relative to the I-3(-)/I- redox-Fermi level was deduced from the shifts in the trap distribution. An expression for the temperature dependence of the open circuit voltage, Uphoto, has been derived. The experimentally observed temperature dependence of U-photo gave values of the activation energy (0.25 eV) and preexponential factor (10(8) s(-1)) for the transfer of electrons from the conduction band of the nanocrystalline TiO2 to triiodide ions.
Original languageEnglish
Pages (from-to)21920-21923
Number of pages4
JournalJournal of Physical Chemistry B
Volume110
Issue number43
DOIs
Publication statusPublished - 2006

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Fermi level
Solar cells
Dyes
Titanium
Electrodes
Electrons
Sensors
Conduction bands
Short circuit currents
Temperature
Open circuit voltage
Titanium dioxide
Activation energy
Ions
Oxidation-Reduction

Cite this

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title = "Direct measurement of the temperature coefficient of the electron quasi-Fermi level in dye-sensitized nanocrystalline solar cells using a titanium sensor electrode",
abstract = "A novel type of dye-sensitized cell (DSC) with a passivated titanium sensor electrode located on top of the nanocrystalline titanium dioxide layer has been used to study the temperature dependence of the electron quasi-Fermi level relative to the I-3(-)/I- redox-Fermi level under short circuit conditions. The results show that the Fermi level decreases with increasing temperature (-1.76 meV K-1) as predicted for diffusive electron transport at short circuit. A smaller temperature dependence (-0.25 meV K-1) of the position of the TiO2 conduction band relative to the I-3(-)/I- redox-Fermi level was deduced from the shifts in the trap distribution. An expression for the temperature dependence of the open circuit voltage, Uphoto, has been derived. The experimentally observed temperature dependence of U-photo gave values of the activation energy (0.25 eV) and preexponential factor (10(8) s(-1)) for the transfer of electrons from the conduction band of the nanocrystalline TiO2 to triiodide ions.",
author = "K Lobato and Peter, {L M}",
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journal = "Journal of Physical Chemistry B",
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TY - JOUR

T1 - Direct measurement of the temperature coefficient of the electron quasi-Fermi level in dye-sensitized nanocrystalline solar cells using a titanium sensor electrode

AU - Lobato, K

AU - Peter, L M

N1 - ID number: ISI:000241553500078

PY - 2006

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N2 - A novel type of dye-sensitized cell (DSC) with a passivated titanium sensor electrode located on top of the nanocrystalline titanium dioxide layer has been used to study the temperature dependence of the electron quasi-Fermi level relative to the I-3(-)/I- redox-Fermi level under short circuit conditions. The results show that the Fermi level decreases with increasing temperature (-1.76 meV K-1) as predicted for diffusive electron transport at short circuit. A smaller temperature dependence (-0.25 meV K-1) of the position of the TiO2 conduction band relative to the I-3(-)/I- redox-Fermi level was deduced from the shifts in the trap distribution. An expression for the temperature dependence of the open circuit voltage, Uphoto, has been derived. The experimentally observed temperature dependence of U-photo gave values of the activation energy (0.25 eV) and preexponential factor (10(8) s(-1)) for the transfer of electrons from the conduction band of the nanocrystalline TiO2 to triiodide ions.

AB - A novel type of dye-sensitized cell (DSC) with a passivated titanium sensor electrode located on top of the nanocrystalline titanium dioxide layer has been used to study the temperature dependence of the electron quasi-Fermi level relative to the I-3(-)/I- redox-Fermi level under short circuit conditions. The results show that the Fermi level decreases with increasing temperature (-1.76 meV K-1) as predicted for diffusive electron transport at short circuit. A smaller temperature dependence (-0.25 meV K-1) of the position of the TiO2 conduction band relative to the I-3(-)/I- redox-Fermi level was deduced from the shifts in the trap distribution. An expression for the temperature dependence of the open circuit voltage, Uphoto, has been derived. The experimentally observed temperature dependence of U-photo gave values of the activation energy (0.25 eV) and preexponential factor (10(8) s(-1)) for the transfer of electrons from the conduction band of the nanocrystalline TiO2 to triiodide ions.

U2 - 10.1021/jp064538o

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