T-ZnOw/ZnONP Double-Layer Composite Photoanode with One-Dimensional Low Resistance Photoelectron Channels for High Efficiency DSSCs

In order to enable the ZnO photoanode obtain superior photovoltaic performance, here we design a T-ZnOw/ZnONP double-layer structure composite photoanode, in which the tetra-needle like zinc oxide whiskers (T-ZnOw) is used as light scattering layer, the needles of T-ZnOw inserted into the ZnO nanoparticles (ZnONP) layer form a unique ZnO needle array structure, which acts as one-dimensional (1-D) low resistance channels and enables photoelectrons reach the FTO conductive layer through relatively small number of interfaces. These characteristics make this double-layer structure photoanode possess lower photoelectron transport resistance and lower photoelectron recombination probability, resulting in higher photovoltaic efficiency compared with the traditional single layer ZnONP photoanode. Moreover, the proposed self-adsorption and self-insertion preparation method of the T-ZnOw layer offer a novel strategy to form 1-D array structure.