How to determine the open circuit voltage of solar cells?

Question

I am reading this paper which is about dye sensitized solar cell, but I do not understand its statement about the open circuit voltage of the cell (page 2242):

In page 2242, the paper says that:

The voltage generated under illumination corresponds to the difference between the Fermi level of theelectron in the $\rm TiO_2$ and the redox potential of the electrolyte.

However, I do not understand the reason behind it. Why does the conduction band energy of $\rm TiO_2$ on the anode affect the open circuit voltage? It seems that it just serve the purpose of conducting electrons. Why wouldn't the cathode material (e.g. Platinum) affect the open circuit voltage of the cell? Also, if we attach a layer of material (e.g. gold or copper wire) to the cathode and anode, will it also affect the open circuit voltage?

Answer 1

The Fermi level of the electron in $TiO_2$ is important because it is at this energy level that the conductive anode picks up the electrons. The electrons that have then made their way through the external circuit have to have enough energy to drive the redox processes that restores the electrolyte and the dye. So, the voltage generated by the cell is the difference between the Fermi level of the electron in the $TiO_2$ and the redox potential of the electrolyte.