ABSTRACT
We report on the effects of surface-modified TiO2 on the open-circuit voltage (Voc) of dye-sensitized solar cells (DSSCs). The TiO2 films were immersed into an aqueous zinc sulfate (ZS) solution to give ZS-modified photoelectrodes. The DSSCs with ZS-modified photoelectrodes showed a considerable improvement in Voc, compared to that of the control device with pristine TiO2 layer. By monitoring open-circuit voltage decay, electrochemical impedance and dark current, it was revealed that the modification of the TiO2 surface by ZS led to a longer electron lifetime due to a reduction of interfacial charge recombination between photo-injected electrons and I−3 ions, and thereby inducing the increase in Voc.
Funding
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2016R1A2B1015037).