Crystalline-TiO₂ flowers for dye sensitized solar cells

Highly dense and well-defined TiO₂ nanoflowers (NFs) are grown by the hydrothermal process on a titanium (Ti) coated FTO substrate. The Ti layer with a thickness of ~500-600 nm is deposited on FTO at room temperature with a pressure of ~5 mTorr using a Ti-source through RF magnetic sputtering. The unique TiO₂ NF thin film substrate is applied as a photoanode for the fabrication of a dye sensitized solar cell (DSSCs). Each NF is made of uniform clover leaf-like petals of an average diameter of ~80-100 nm. The synthesized TiO₂ NFs possesses a pure anatase phase with good crystal quality. The fabricated DSSC with TiO₂ NF thin film photoanode accomplishes a reasonably good overall solar-to-electricity conversion efficiency (η) of ~3.64% with a high short circuit photocurrent density (JSC) of ~9.6 mA cm^-2. The improved performance and photocurrent density are explained by the charge transport time, diffusion coefficient, diffusion length and charge collection efficiency of the fabricated DSSC.