Determination of the electron diffusion length in dye-sensitized solar cells by substrate contact patterning

Halina K Dunn, Per-Oskar Westin, Daniel R Staff, Laurence M Peter, Alison B Walker, Gerrit Boschloo, Anders Hagfeldt

Research output: Contribution to journalArticle

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Abstract

A new method to estimate the electron diffusion length in dye-sensitized solar cells (DSCs) is presented. DSCs were fabricated on conducting glass substrates that were patterned by laser ablation of the fluorine-doped tin oxide coating to form parallel contact strips separated by uncontacted strips of the same width. The relative collection efficiency was measured as a function of the gap between the contact strips, which determines the lateral distance traveled by electrons to reach the contacts. To avoid complications arising from nonlinear recombination kinetics, current measurements were performed using small amplitude perturbations of the electron density close to open circuit and the maximum power point to minimize electron density gradients in the film. One and two-dimensional solutions of the continuity equation for electron transport and back reaction predict that the relative collection efficiency should fall as spacing between the contact strips exceeds the electron diffusion length and electrons are lost by back electron transfer during transit to the contacts. Measurements of the relative collection efficiency were fitted to the predicted dependence of the collection efficiency on the spacing between the contact strips to obtain the value of the electron diffusion length. The diffusion length is found to increase with voltage both at open circuit and at the maximum power point.
LanguageEnglish
Pages13932-13937
Number of pages6
JournalJournal of Physical Chemistry C
Volume115
Issue number28
DOIs
StatusPublished - 21 Jul 2011

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electron diffusion
diffusion length
strip
solar cells
dyes
Electrons
Substrates
Carrier concentration
spacing
electrons
continuity equation
transit
Fluorine
Networks (circuits)
tin oxides
laser ablation
Electric current measurement
fluorine
Laser ablation
Tin oxides

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Determination of the electron diffusion length in dye-sensitized solar cells by substrate contact patterning. / Dunn, Halina K; Westin, Per-Oskar; Staff, Daniel R; Peter, Laurence M; Walker, Alison B; Boschloo, Gerrit; Hagfeldt, Anders.

In: Journal of Physical Chemistry C, Vol. 115, No. 28, 21.07.2011, p. 13932-13937.

Research output: Contribution to journalArticle

Dunn, Halina K ; Westin, Per-Oskar ; Staff, Daniel R ; Peter, Laurence M ; Walker, Alison B ; Boschloo, Gerrit ; Hagfeldt, Anders. / Determination of the electron diffusion length in dye-sensitized solar cells by substrate contact patterning. In: Journal of Physical Chemistry C. 2011 ; Vol. 115, No. 28. pp. 13932-13937
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AU - Boschloo,Gerrit

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