Improved electrochemical and photovoltaic performance of dye sensitized solar cells based on PEO/PVDF–HFP/silane modified TiO₂electrolytes and MWCNT/Nafion^®counter electrode

Abstract

Polymer blend electrolyte membrane was prepared for dye sensitized solar cells based on poly ethylene oxide and polyvinylidene fluoride-co-hexaflouropropylene (PVDF-HFP) filled with surface modified Titanium dioxide (M-TiO 2 ) nanofillers. The surface of TiO 2 was modified using Aminopropyltrimethoxysilane. The electrochemical studies indicated that the addition of surface modified nanoparticles increase the ionic conductivity up to 7.21x 10 -4 S/cm for 7 wt%, whereas the ionic conductivity about 8.14×10 -5 S/cm with the addition of unmodified counterpart as the filler into the PEO/PVDF-HFP blend system. In addition to this ionic mobility, charge carrier concentration, ion diffusion coefficient also found to increase with the addition of surface modified TiO 2 nanoparticles. Wide angle X-ray diffraction (WAXD) results showed the change in the crystalline phase of PEO/PVDF-HFP blend electrolyte with the addition of M-TiO 2 . The influence of the TiO 2 nanoparticles surface functionality on the degree of crystallinity of the polymer matrix was analyzed using differential scanning Calorimetry (DSC). Thermo mechanical behavior of the composite membranes was studied by dynamical mechanical Analysis (DMA). The thermo gravimetric investigations (TGA) of membranes indicated the thermal degradation temperatures of hybrid nanocomposites were enhanced upon the addition of nanosized inorganic fillers. The morphological characterizations were carried out by atomic force microscopy (AFM). The solid state dye sensitized solar cell has been fabricated by using silane modified TiO 2 /PEO/PVDF-HFP polymer nanocomposites electrolyte, multiwalled carbon nanotube (MWCNT)/Nafion ® as counter electrode. The photovoltaic characteristics of constructed cells showed an enhancement of open circuit voltage (V oc ) from 0.62 to 0.71 V andthe best efficiency achieved about 2.84%. The enhancement of DSSC was further confirmed by electrochemical impedance spectra (EIS) spectra studies for lowest Warburg resistance (R diff ).

Solid state metal-free eosin-Y dye sensitized solar cell based on PVdF-HFP electrolytes: combined effect of surface modified TiO2 and plasticizer on electrochemical and photovoltaic properties

“…It indicates that a large number of intermolecular and intramolecular hydrogen bonds are formed by the interactions of solvent, plasticizers, and PVdF-HFP. The intensity of -OH stretching was decreased with the addition of S-TiO 2 within PVdF-HFP electrolyte membrane, which indicates the hydrolysis condensation reaction of APS molecules present on the TiO 2 nanoparticles [8].…”

“…The TiO 2 photoanode and Pt counter electrodes were prepared as reported in our earlier works [8]. The optimized TiO 2 / PVdF-HFP and silane-modified TiO 2 /PVdF-HFP polymer composite electrolytes were spread on the dye-sensitized TiO 2 photoanode.…”

“…Similarly, amorphous hexafuoropropylene (HFP) units increase the plasticity and enhance ionic conductivity. Even in the presence of HFP, the ionic conductivity of PVdF-HFP is approximately 10 −10 S/cm [8].…”

“…The silane molecules on the surface of TiO 2 formed the hydrated oxides and captured the formation of hydroxyl radicals. Therefore, it will help to reduce the photocatalytic activity of pure TiO 2 nanoparticles [8].…”

“…The hybrid network structure of gel/polymer electrolytes has both cohesive properties of solids and diffusive transport of liquids and is characterized by high ionic conductivity and long-term stability. A large number of solid/gel polymer electrolytes and blends/nanocomposites based on poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and poly(methyl methacrylate) (PMMA), poly(ethylene glycol) (PEG), poly vinylidene fluoride (PVdF), poly(ether urathane) (PEUR), polyvinyl pyrrolidone, poly(dimethyl siloxane), poly(acrylonitrile) (PAN), etc., have been reported [8][9][10][11][12][13][14][15][16]. Among the polymers used in electrochemical device applications, a flouro polymer like PVdF has received great attention because of the presence of fluorine that has the relatively smallest ionic radius and high electronegativity.…”