Electron diffusion and back reaction in dye-sensitized solar cells: the effect of nonlinear recombination kinetics

J Villanueva-Cab, Hongxia Wang, G Oskam, Laurence M Peter

Research output: Contribution to journalArticlepeer-review

102 Citations (Scopus)

Abstract

The electron collection efficiency in dye-sensitized solar cells (DSCs) is usually related, to the electron diffusion length, L = (D tau)(1/2), where D is the diffusion coefficient of mobile electrons and r is their lifetime, which is determined by electron transfer to the redox electrolyte. Analysis of incident photon-to-current efficiency (IPCE) spectra for front and rear illumination consistently gives smaller values of L than those derived from small amplitude methods. We show that the IPCE analysis is incorrect if recombination is not first-order in free electron concentration, and we demonstrate that the intensity dependence of the apparent L derived by first-order analysis of IPCE measurements and the voltage dependence of L derived from perturbation experiments can be fitted using the same reaction order, gamma approximate to 0.8. The new analysis presented in this letter resolves the controversy over why L values derived from small amplitude methods are larger than those obtained from IPCE data.
Original languageEnglish
Pages (from-to)748-751
Number of pages4
JournalJournal of Physical Chemistry Letters
Volume1
Issue number4
Early online date29 Jan 2010
DOIs
Publication statusPublished - 18 Feb 2010

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