Enhancing the ionic transport of PEO-based composite polymer electrolyte by addition of TiO₂ nanofiller for quasi-solid state dye-sensitized solar cells

Abstract

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)-TiO₂-LiI-I₂ system. Effects of the concentration of TiO₂ nanofiller on the electrochemical properties of the PEO-based composite polymer electrolytes have been investigated. The experimental results show that the presence of TiO₂ in the PEO-based electrolyte changes the phase of the polymer. Also, the addition of TiO₂ noticeably increases the ionic conductivity of the PEO-based electrolytes. At optimized TiO₂ 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 TiO₂ 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⁻/I₃ ⁻ redox couple, resulting in the increases of the conductivity and the current density of QS-DSSC.