Correlations between morphology and photoelectrical properties of single-crystal rutile TiO2 nanorods
Oriented single-crystal rutile TiO2 nanorod arrays were grown directly on transparent conductive fluorine-doped tin oxide (FTO) substrates through a facile hydrothermal method with different growth times and temperatures. It was found that reaction temperature significantly affected morphology, crystallinity and photoelectrical performance of TiO2, while growth time demonstrated less influence. Under the irradiation, short-circuit photocurrent density of TiO2 increased along with the reaction temperature until nanorod aggregation arose and the optimal value reached to 0.91 mA/cm2 at 180 °C. In UV-visible diffuse reflectance spectrum and external quantum efficiency (EQE) measurements, red shifts appeared with the increase of growth time and temperature, which can be ascribed to the improvement of rutile crystallinity. Furthermore, it was for the first time proved that sintering treatment didn't improve the crystallinity of TiO2 on FTO substrata. The highest photocurrent density of 3.36 mA/cm2 and EQE value of 2 2.2% a p p earee d after sinte ring at 300 °C, while the decay at high temperatures may be caused by the aggregation and fracture of the nanorods, consistent with the effects of reaction temperature. In summary, long, oriented, and separated TiO2 nanorods with the elimination of organic titanium precursor on their surface demonstrate highly efficient photoelectrical characteristics.
Physics, Astronomy, and Materials Science
Crystallinity, Diameter, Length, Photoelectrical conversion, TiO Nanorod array 2
Sun, Qiong, Xianmiao Sun, Yang Li, Liyan Yu, and Lifeng Dong. "Correlations between morphology and photoelectrical properties of single-crystal rutile TiO2 nanorods." Science of Advanced Materials 5, no. 9 (2013): 1221-1230.
Science of Advanced Materials