科研之友
微信
新浪微博
Facebook
分享链接
摘要
Well-aligned TiO2 nanowire arrays are fabricated through a simple hydrothermal method and sensitized with electrodeposited CdSe nanoparticles. Annealing treatments at various temperatures (350 degrees C, 380 degrees C, 400 degrees C and 450 degrees C) are used to improve the performance of the as-deposited photoelectrode and the effects of various annealing atmospheres (air, O-2, N-2, Ar and vacuum) are further investigated. Although the film is only 2 mu m thick, a significant photocurrent density of 8.83 mA cm(-2) is observed under 100 mW cm(-2) illumination (AM 1.5 G) for the sample annealed at 400 degrees C in air, which is 5.69 times higher than that of the as-deposited sample and much better compared with that of the samples annealed in other environments. Careful investigation on the annealing effect is performed with a range of analytical techniques, such as SEM, TEM, HRTEM, EDX, UV-vis absorption spectra, and XRD. In particular, HRTEM observation affords a further insight into the exact change in CdSe crystalline structure annealed at different temperature. The results indicate that the crystal structure of CdSe nanoparticles and the interface between TiO2 and CdSe are improved with appropriate annealing below 400 degrees C, leading to an enhancement of performance. On the other hand, over-annealing at 450 degrees C results in severe migration and oxidation of CdSe, and leads to a poor photoelectric performance. A better understanding of the influence of the annealing environment is obtained through the adoption of different annealing atmospheres at 400 degrees C. It is found that both O-2 and N-2 have a more positive effect on the annealing process compared with Ar and vacuum, while air is found to be the favorite environment for annealing treatment.
- 出版日期2011
- 单位北京大学
