LAUSR

Sodium-carboxymethylcellulose (NaCMC) films have been developed by solution casting technique. The films were soaked into an optimized aqueous polysulphide electrolyte containing 4 M sodium sulphide (Na 2 S) and 1 M sulphur (S). The optimized aqueous polysulphide electrolyte has the ambient conductivity of (1.46 ± 0.02) × 10 -1 S cm -1 . The NaCMC films were soaked for different durations of 30, 60, 68 and 75 s. The highest room temperature ionic conductivity (RTIC) of (2.79 ± 0.09) × 10 -5 S cm -1 is exhibited by NaCMC film soaked in polysulphide electrolyte for 68 s. The conductivity-temperature relationship of NaCMC-based polysulphide solid polymer electrolytes (SPEs) follows the Arrhenius rule. The highest conducting SPE exhibits the lowest activation energy ( E A ) value of 0.38 eV. Ionic coefficient of diffusion ( D ), ionic mobility ( μ ) and free ions concentration ( n ) of the SPEs were determined. The newly developed SPEs are used as electrolyte in quantum dot-sensitized solar cells (QDSSCs) application with the configuration FTO/TiO 2 /CdS/ZnS/SPE/Pt/FTO. Under 1000 W m -2 illumination, QDSSC with CMC-68 SPE exhibits the highest power conversion efficiency (PCE) of 0.90%. The values of short circuit current ( J SC ) and PCE are closely related to electron lifetime and recombination rate.