A polymer electrolyte containing ionic liquid for possible applications in photoelectrochemical solar cells

Various iodide ion conducting polymer electrolyteshave been studied as candidate materials for fabricatingphotoelectrochemical (PEC) solar cells and energystorage devices. In this study, enhanced ionic conductivityvalues were obtained for the ionic liquid tetrahexylammoniumiodide containing polyethylene oxide (PEO)-basedplasticized electrolytes. The analysis of thermal propertiesrevealed the existence of two phases in the electrolyte, andthe conductivity measurements showed a marked conductivityenhancement during the melting of the plasticizer-richphase of the electrolyte. Annealed electrolyte samplesshowed better conductivity than nonannealed samples,revealing the existence of hysteresis. The optimum conductivitywas shown for the electrolytes with PEO:salt=100:15 mass ratio, and this sample exhibited the minimumglass transition temperature of 72.2 \ub0C. For this optimumPEO to salt ratio, the conductivity of nonannealed electrolytewas 4.4 710−4 S cm−1 and that of the annealed samplewas 4.6 710−4 S cm−1 at 30 \ub0C. An all solid PEC solar cellwas fabricated using this annealed electrolyte. The shortcircuit current density (ISC), the open circuit voltage (VOC),and the power conversion efficiency of the cell are0.63 mA cm−2, 0.76 V, and 0.47% under the irradiation of600 W m−2 light