Modification of a TiO2 photoanode by using Cr-doped TiO2 with an influence on the photovoltaic efficiency of a dye-sensitized solar cell

Abstract

This work reports on the preparation of Cr-doped TiO 2 (Cr-TiO 2 ) and its utilization in the photoanode of a dye-sensitized solar cell (DSSC). Pure TiO 2 and 10% Cr-TiO 2 sols were individually obtained via hydrolysis followed by a hydrothermal process at 250 C for 12 h. The TiO 2 sol was first coated on a fluorine-doped tin oxide (FTO) substrate using a polymer binder and sintered at 500 C for 30 min. The Cr-TiO 2 sol was then deposited on the TiO 2 layer through the same procedure, thus forming two different layers on the substrate. We found that the photovoltaic efficiency was improved by ca. 18.3% when the double layer was adopted as the photoanode of a DSSC instead of only the TiO 2 layer. We assume that this improvement was caused by the repression of electron recombination occurring in the double layer. Further characterizations were carried out to clarify the function of the double layer.

Effects of metal hydroxide-treated photoanode on the performance of hybrid solar cells

“…4. As a result, the conduction band edge of NaOHeTiO 2 /FTO was shifted to a more negative potential compared to that of our TiO 2 /FTO or the reference electrode [47,48]. This resulted in the larger potential difference between TiO 2 Fermilevel and an electrolyte, thus V oc could have increased when NaOHeTiO 2 /FTO was used as the photoanode.…”

“…Band edge positions and band-gap energies of various anatase TiO 2[47,48] and our samples on a normal hydrogen electrode potential (NHE).…”

Electronic Properties of Vanadium‐Doped TiO2

“…Therefore, significant efforts have been made over the last 20 years to develop modified TiO 2 particles that are active under visible-light irradiation. Doping with metals such as vanadium, [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] silver, [28] nickel, [29,30] and chromium [31,32] has been proved to be a promising strategy to modify the photoelectrochemical and photocatalytic properties of TiO 2 . Doping with some elements induces energy levels in the band gap, which may increase the yield for electron-hole pair formation under illumination with visible light and thereby, may enhance photocatalytic activity.…”

Solar-to-Electric Performance Enhancement by Titanium Oxide Nanoparticles Coated with Porous Yttrium Oxide for Dye-Sensitized Solar Cells

“…31,32 Because TiO 2 and Y 2 O 3 constitute a heterojunction, the EFs will align after establishing equilibrium. 33,34 In our case, a downward shift in the Fermi energy level of the Y 2 O 3 and an upward shift in the Fermi energy level of the TiO 2 will occur, thus raising the Fermi level of T@XY NPs and subsequently the V OC of their DSSCs compared to that with pure TiO 2 NPs and its DSSC.…”