A Novel Composite Polysaccharide/Inorganic Oxide Electrolyte for High Efficiency Quasi-solid-state Dye-sensitized Solar Cell

摘要

A new composite polymer electrolyte consisting of low-molecular mass polysaccharide (agarose) filled with titanium oxide and containing LiI and I_2 was developed. The introduction of the inorganic filler (TiO_2) into the agarose polymer matrix changes the thermal and ionic conductive properties of host polymer electrolyte. The polysaccharide electrolyte with different inorganic filler TiO_2 concentrations (0-30 wt%) is studied systematically by differential scanning calorimetry (DSC) and the AC impedance spectra. Upon addition of the inorganic oxide, the glass transition temperature (T_g) of the electrolyte decreases within the range of 0-2.5 wt% TiO_2 changed electrolytes, which results in high conductivity in these electrolytes. Then the T_g increases with the TiO_2 content until 30 wt% and the ionic conductivity of the electrolyte decreases in this concentration range. From the electrochemical analysis, it is observed that the electron lifetime in TiO_2 of DSSC decreases with inorganic filler contents, which results in lower Voc in the high TiO_2 content added DSSC. Based on these results, the optimized efficiency of titania added DSSC is 4.74% at 2.5 wt% titania concentration.