Titanium dioxide coated zinc oxide nanostrawberry aggregates for dye-sensitized solar cell and self-powered UV-photodetector.

Abstract: We report ZnO nanostrawberry aggregates (ZnO NS) structure that serves as photoanode for efficient DSSCs as it offers a large specific surface area, excellent light scattering characteristics, and low degree of charge recombination simultaneously. The short-circuit current density (J sc) of the ZnO NS DSSC is more than two times higher than that of commercially-obtained ZnO nanocrystallines (ZnO NC) due to the excellent light scattering of the ZnO NS film, resulting in a 46% improvement in the power conversion efficiency (PCE). The introduction of TiO2 coating layer on to the ZnO NS (ZnO NS–TiO2) results in more than 82% enhancement in the PCE from 1.40% to 2.56%. Moreover, the photoelectrochemical cell (PECC) with unsensitized ZnO NS–TiO2 film as photoanode is applied to detect the UV light without a power source. This self-powered UV-photodetector exhibits a high on/off ratio of 37,900, a fast rise time of 0.022 s and a decay time of 0.009 s for J sc signal, together with the excellent self-powered, “visible blind” characteristics and photosensitivity linearity in a wide light intensity range. [Copyright &y& Elsevier]