摘要
A flat thin TiO2 film was employed as the photo-electrode of a dye sensitized solar cell （DSSC）, on which only a geometrical mono-layer of dye was attached. The effect of sur- face protonation by HCI chemical treatment on the performance of DSSCs was studied. The results showed that the short-circuit current Jsc increased significantly upon the HCI treatment, while the open-circuit voltage Voc decreased slightly. Compared to the untreated DSSC, the Jsc and energy conversion efficiency was increased by 31% and 25%, respectively, for the 1 mol/L HCI treated cell. TiO2 surface protonation improved electronic coupling between the chemisorbed dye and the TiO2 surface, resulting in an enhanced electron in- jection. The decreased open-circuit voltage after TiO2 surface protonation was mainly due to the TiO2 conduction band edge downshift and was partially caused by increased electron recombination with the electrolyte. In situ Raman degradation study showed that the dye stability was improved after the TiO2 surface protonation. The increased dye stability was contributed by the increased electron injection and electron back reaction with the electrolyte under the open-circuit condition.
