Utilizing Chromium as the Photoanode Substrate in Dye-Sensitized Solar Cells

Fluorine-doped tin oxide (FTO) is replaced with chromium as the photoanode substrate in a dye-sensitized solar cell (DSSC), and the effect of chromium(III) oxide on the electron lifetime and the performance of a Cr-based DSSC is investigated and compared with conventional FTO-based devices. It is shown that Cr is stable in the chemically aggressive iodide-based electrolyte, which can be attributed to the compact oxide overlayer. The chromium-oxide layer also effectively blocks electron recombination from the substrate, while hindering electron transfer from the TiO2 film to the Cr electrode. We show that pretreatment of the electrodeposited Cr film with a colloidal sol of TiO2 is extremely effective in reducing the electron-transfer resistance at the Cr-TiO2 interface. This effect may be attributed to both increasing interconnections between the mesoporous layer of TiO2 and the rough electrodeposited layer of Cr, as well as inhibition of the thickening Cr2O3 layer during the thermal process. The colloidal sol treatment increases the cell efficiency by 73% of the initial value (from 2.58 to 4.47%) and the fill factor from 0.38 to 0.64.