Assessment of TiO2 Blocking Layers for CuII/I-Electrolyte Dye-Sensitized Solar Cells by Electrochemical Impedance Spectroscopy

Hannes Michaels; Marina Freitag

doi:10.1021/acsaem.1c03433

Assessment of TiO₂ Blocking Layers for Cu^II/I-Electrolyte Dye-Sensitized Solar Cells by Electrochemical Impedance Spectroscopy

ACS Appl Energy Mater. 2022 Feb 28;5(2):1933-1941. doi: 10.1021/acsaem.1c03433. Epub 2022 Feb 11.

Authors

Hannes Michaels^{1

2}, Marina Freitag^{1

2}

Affiliations

¹ Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 75120, Sweden.
² School of Natural and Environmental Science, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom.

Abstract

The TiO₂ blocking layer in dye-sensitized solar cells is the most difficult component to evaluate at thicknesses below 50 nm, but it is crucial for the power conversion efficiency. Here, the electrode capacitance of TiO₂ blocking layers is tested in aqueous [Fe(CN)₆]^3-/4- and correlated to the performance of photoanodes in devices based on a [Cu(tmby)₂]^2+/+ electrolyte. The effects of the blocking layer on electronic recombination in the devices are illustrated with transient photovoltage methods and electrochemical impedance analysis. We have thus demonstrated a feasible and facile method to assess TiO₂ blocking layers for the fabrication of dye-sensitized solar cells.