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Updated: Mar 8, 2026

Electrochemical Impedance Spectroscopy as a Tool for Electrochemical Rate Constant Estimation
Published on: October 10, 2018
On how electron density affects the redox stability of phenothiazine sensitizers on semiconducting surfaces
Valerie A Chiykowski1, Brian Lam1, Chuan Du1
1Departments of Chemistry and Chemical & Biological Engineering, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada. cberling@chem.ubc.ca.
Abstract:
The stabilities of three organic dyes that differ only by two substituents (-OMe, -H and -Br) about the phenothiazine donor unit were evaluated when immobilized on a semiconductor surface. All three dyes delivered modest power conversion efficiencies (PCEs) in the dye-sensitized solar cell (DSSC), but maintained 75% of their initial PCE over 300 h of sustained simulated sunlight. Electron-donating substituents increased the stability of the phenothiazine radical unit created after light-induced charge injection into the semiconductor; however, this did not translate to higher DSSC stability, which appears to be more sensitive to the basicity of the anchoring group for this series.
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