Journal of Power Sources, Vol.239, 458-465, 2013
Titanium dioxide coated zinc oxide nanostrawberry aggregates for dye-sensitized solar cell and self-powered UV-photodetector
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 0.009s for J(sc) signal, together with the excellent self-powered, "visible blind" characteristics and photosensitivity linearity in a wide light intensity range. (C) 2013 Elsevier B.V. All rights reserved.
Keywords:Zinc oxide nanostrawberry;Dye-sensitized solar cells;Self-powered;UV-photodetector;Light scattering