25In this work, a hybrid polymer electrolyte membrane based on poly(ethylene oxide) 26 (PEO)/poly(vinylidene fluoride-co-hexaflouropropylene) (PVDF-HFP) blend containing 27 chemically exfoliated nanosilicate platelets was prepared to replace the conventionally used 28 liquid electrolyte for dye sensitized solar cells (DSSC). The layered montmorillonite 29 nanosilicates were chemically exfoliated using aminopropyltrimethoxy silane (APS). The 30 modifications on nanosilicate by APS molecules were characterized by Fourier infrared 31 spectroscopy (FTIR) and wide angle X-ray diffraction (WAXD). The polymer composite 32 membranes were subjected to FTIR, WAXD and Differential scanning calorimetry (DSC) 33 studies in order to understand the intercalation/exfoliation and crystallinity. The surface and 34 porous structure of composite membranes were examined by scanning electron microscope 35 (SEM) analysis and mercury porosimetry. The porosity and weight uptake enhanced with the 36 addition of surface modified nanoplatelets. The UV-VIS spectra indicated an increase in free ion 37concentration with the addition of exfoliated nanoplatelets, which led to an increase in the ionic 38 conductivity up to 2.52 × 10 -3 S/cm for 6 wt% and it decreased afterwards. On the other hand, 39 same amount of unmodified counterpart achieved an ionic conductivity of about 5.41×10 -4 S/cm.
40In addition to this, an increase in ion concentration and ionic diffusion coefficient was found 41 with the addition of surface modified MMT platelets. The linear steady state voltammetry 42 indicated that incorporation of surface modified nanoplatelets reduces the ionic diffusion length 43 and increases the diffusion coefficient to about 4.8×10 -9 cm 2 /s. The photovoltaic performance 44 exhibits an enhanced open circuit voltage (V oc ) 0.73 V and short circuit current (J sc ) 7.7 mA/cm 2 45 under the illuminations of 100mW/cm 2 . 46 47 In 1991, the first original Dye Sensitized Solar Cell (DSSC) was proposed by O'rigan 49 and Gratzel. 1 After the invention of DSSC, it has attracted significant attention owing to its 50 simple structure, low material cost, and low energy consumption for production. 2 The typical 51 DSSC consists of dye adsorbed TiO 2 as photo anode, I-/I 3 redox electrolyte and thin Pt layer as a 52 counter electrode. 3 Till date, the best solar conversion efficiency achieved for a liquid electrolyte 53 based DSSC is about 11-13%. 4 However, low durability, solvent leakage, dye desorption and 54 electrode corrosion in DSSC due to the liquid electrolytes restricts the commercial viability. In 55 order to replace the conventional liquid electrolyte system, many solid state alternatives such as 56 P-type semiconductor, organic hole conductors, room temperature molten salts, polymeric or gel 57 materials comprising redox active electrolyte solution have been studied for DSSC applications. 5-58 7 Among the solid alternatives, polymer gel electrolytes have several advantages like limited 59 internal shorting, low vapor pressure, excellent c...
