In DSSC, TiO2 photoanode with Nb2O5 blocking layer (FTO/TiO2 interface layer) can prevent electron recombination due to its higher CB edge than TiO2. But, how will electrons be injected from TiO2 to Nb2O5 or how will electron transfer from lower CB to higher CB?
The TiO2 photo-anode is usually sensitized with a dye that absorbs light and produces electron-hole pairs. Following photo-excitation, electrons in the TiO2 conduction band (CB) migrate to decrease the dye, creating injected electrons. To prevent electron recombination, a layer of Nb2O5 is added.
The Nb2O5 layer has been chosen because it has a higher CB edge than TiO2. The energy level alignment ensures that electrons are energetically favorable for moving from TiO2 to Nb2O5.The FTO substrate acts as the conductive support for the photo-anode...
Thank you, Hadush Asgedom sir.
As per your statement, the photoexcited electron has that much potential. Am I right?
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