Artificial photosynthesis based on ruthenium(II) tetrazole-dye-sensitized nanocrystalline TiO2 solar cells

Eosin-Y sensitized core-shell TiO2-ZnO nano-structured photoanodes for dye-sensitized solar cell applications

In the current investigation, TiO₂ and TiO₂-ZnO (core-shell) spherical nanoparticles were synthesized by simple combined hydrolysis and refluxing method. A TiO₂ core nanomaterial on the shell material of ZnO was synthesized by utilizing variable ratios of ZnO. The structural characterization of TiO₂-ZnO core/shell nanoparticles were done by XRD analysis. The spherical structured morphology of the TiO₂-ZnO has been confirmed through field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) studies. The UV-visible spectra of TiO₂-ZnO nanostructures were also compared with the pristine TiO₂ to investigate the shift of wavelength. The TiO₂-ZnO core/shell nanoparticles at the interface efficiently collect the photogenarated electrons from ZnO and also ZnO act a barrier for reduced charge recombination of electrolyte and dye-nanoparticles interface. This combination improved the light absorption which induced the charge transfer ability and dye loading capacity of core-shell nanoparticles. An enhancement in the short circuit current (J_sc) from 1.67 mA/cm² to 2.1 mA/cm² has been observed for TiO₂-ZnObased photoanode (with platinum free counter electrode), promises an improvement in the energy conversion efficiency by 57% in comparison with that of the DSSCs based on the pristine TiO₂. Henceforth, TiO₂-ZnO photoelectrode in ZnO will effectively act as barrier at the interface of TiO₂-ZnO and TiO₂, ensuring the potential for DSSC application.