Hierarchical TiO2 nanoflowers/nanosheets array film: synthesis, growth mechanism and enhanced photoelectrochemical properties

The possible growth mechanism of a hierarchical TiO2 nanoflower/nanosheet (NFS) array was put forward in the work. The TiO2 NFS array film perpendicularly grown on transparent conductive fluorine-doped tin oxide (FTO) glass substrates was prepared via a one-step template-free hydrothermal method. The NFS array film was formed by the self assembly of nanosheets with exposed highly reactive {001} facets. Titanium butoxide and ammonium hexafluorotitanate ((NH4)(2)TiF6) were used as titanium precursor and morphology controlling agent, respectively. The growth process of TiO2 NFS array was investigated according to the SEM images and XRD patterns of the products at different reaction stages. The tractable morphology controlling agent played a key role in the preparation of pure anatase TiO2 and affected the thickness of the nanosheets. This study provides new insights into the synthesis of hierarchical anatase TiO2 nanostructures with a high percentage of {001} facets. In addition, the photoelectrochemical performance of the CdS QDs sensitized TiO2 NFS array film was assessed, indicating a variety of applications such as dye-sensitized or quantum dot-sensitized solar cells fields.