A composite polymer electrolyte comprising poly(vinyl alcohol)–poly(4-styrenesulphonic acid) with bariumchloride dihydrate (BaCl$_2$·2H$_2$O) salt complex has been synthesized following the usual solution casting. The ionic conductivity of polymer electrolyte was analysed by impedance spectroscopy. The highest room temperature (at 30$^{\circ}$C) conductivity evaluated was 9.38 $\times$ 10$^{−6}$ S cm$^{−1}$ for 20 wt% loading of BaCl$_2$ in the polymer electrolyte. This has been referred to as the optimum conducting composition. The temperature-dependent ionic conductivity of the polymer electrolyte exhibits the Arrhenius relationship, which represents the hopping of ions in polymer composites. Cation and anion diffusion coefficients are evaluated using the Trukhan model. The transference number and enhanced conductivity imply that the charge transportation is due to ions. Therefore this polymer electrolyte can be further studied for the development of electrochemical device applications.

Boron dipyrromethene (BODIPY) is a highly promising candidate for use in dye-sensitized solar cell (DSSC), because of its attractive absorption characteristics such as strong extinction coefficients in the visible and near-IR ranges (70000–80000 M$^{−1}$ cm$^{−1}$), large quantum yields, longer excited-state lifetime and also high solubility in many organic solvents.Moreover, the absorption peaks can be shifted towards longer wavelengths when functionalized at suitable positions of the BODIPY core. Herein, on the basis of density functional theory (DFT) and time-dependent DFT, we provide theopto-electronic properties of BODIPY core-functionalized dyes to see their applicability in organic DSSC. Our systematic analyses reveal that the 2,6 substituted dyes show better photovoltaic properties compared to the 3,5 substituted ones. On the basis of empirical relationship, we have also calculated the photo-induced electron injection times of some dye-TiO$_2$ composites, which seem to be in the ultrafast time scale, thus rendering them a promising candidate for DSSC applications. Our theoretical studies provide that judiciously designed BODIPY core-derived dyes show certain unique spectroscopic andelectronic features that make them highly advantageous in DSSC applications as compared to other organic dyes.