Working electrodes and counter electrodes

Working electrodes for dye-sensitized solar cells (DSC)

[electrodes] The working electrode of DSCs consists of a porous film of metal oxide nanocrystals that sits on a conducting glass substrate (glass coated with a thin layer of fluorine-doped tinoxide, FTO).

The metal oxides that we study are TiO2, ZnO and SnO2. These materials are transparent or white and don’t absorb visible light. Dye molecules attached on the large surface area of the porous film are responsible for absorption of sunlight. The metal oxides accept electrons from the excited dyes and transport them to the substrate.

In our research we study and optimize the charge transport and light absorption of the porous film and try to minimize loss reactions.

Counter electrodes for DSCs [Charge 1]

Counter electrode (CE) is the layer to reduce the redox species oxidized at the working electrode. Normally, platinum (Pt) is used for this layer due to its high catalytic property. A thin layer of Pt nanoparticles is deposited on FTO by thermal decomposition, sputtering or electrochemical deposition.

Its charge transfer resistance, which is strongly related to fill factor in the solar cells, is characterized by Impedance spectroscopy. [Charge 2]

By improving the catalytic property and by increasing the surface area, the charge transfer resistance at counter electrode can be reduced. Preparation conditions and new materials are investigated to improve the fill factor for DSCs.