The Effect of a Sol-gel Formed TiO2 Blocking Layer on the Efficiency of Dye-sensitized Solar Cells

The effect of a dense TiO2 blocking layer prepared using the sol-gel method on the performance of dye-sensitized solar cells was studied. The blocking layer formed directly on the working electrode, separated it from the electrolyte, and prevented the back transfer of electrons from the electrode to the electrolyte. The dye-sensitized solar cells were prepared with a working electrode of fluorine-doped tin oxide glass coated with a blocking layer of dense TiO2, a dye-attached mesoporous TiO2 film, and a nano-gel electrolyte, and a counter electrode of Pt-deposited FTO glass. The gel processing conditions and heat treatment temperature for blocking layer formation affected the morphology and performance of the cells, and their optimal values were determined. The introduction of the blocking layer increased the conversion efficiency of the cell by 7.37% for the cell without a blocking layer to 8.55% for the cell with a dense TiO2 blocking layer, under standard illumination conditions. The short-circuit current density (J(sc)) and open-circuit voltage (V-oc) also were increased by the addition of a dense TiO2 blocking layer.