Enhancing the Ionic Transport of PEO-Based Composite Polymer Electrolyte by Addition of TiO_2 Nanofiller for Quasi-Solid State Dye-Sensitized Solar Cells

摘要

For the application to quasi-solid state dye-sensitized solar cells (QS-DSSCs), we have prepared composite polymer electrolytes with a poly(ethylene oxide) (PEO)-TiO_2-LiI-I_2 system. Effects of the concentration of TiO_2 nanofiller on the electrochemical properties of the PEO-based composite polymer electrolytes have been investigated. The experimental results show that the presence of TiO_2 in the PEO-based electrolyte changes the phase of the polymer. Also, the addition of TiO_2 noticeably increases the ionic conductivity of the PEO-based electrolytes. At optimized TiO_2 concentration of 15 wt%, the composite polymer electrolyte exhibited a maximum value of ionic conductivity, and leads to remarkable enhancement of the photovoltaic performance of the QS-DSSC. This indicates that the incorporation of TiO_2 to the PEO-based electrolytes gives rise to the reduction of the crystallinity of the polymer and the enhancement of the mobility of the I~-/I_3~- redox couple, resulting in the increases of the conductivity and the current density of QS-DSSC.