Improvement in open circuit voltage of solar cells with zinc sulfate-modified photoelectrodes

ABSTRACT

We report on the effects of surface-modified TiO₂ on the open-circuit voltage (V_oc) 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 V_oc, 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 V_oc.

KEYWORDS:

• Dye-sensitized solar cells
• zinc sulfate
• photoelectrode
• charge recombination

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).