TiO2纳米管刻蚀生长机理及其光电性能（英文）

Growth Mechanism of TiO2 Nanotube Arrays by Etching Treatment and Their Photoelectric Property

采用盐酸将有序排列的TiO2纳米棒刻蚀成纳米管,并推测了生长机理。刻蚀过程中,凹陷沿棒生长方向自上而下由内而外产生,最终形成管式结构。大量纳米线围绕成具有方形空心截面的纳米管,高温下将完全分裂。TiO2纳米管的光电转换效率远高于纳米棒,最高值(3.26%)出现在140℃刻蚀温度。纳米管比表面积增加和长度缩短分别对光电性能起到正反两方面作用。此外,煅烧导致纳米管断裂和聚集,光生载流子定向转移的难度增加,光电转换效率降低。

In this research, densely aligned TiO2 nanorods are etched into nanotubes by hydrochloric acid, and the growth mechanism is also supposed. During the etching process, the dents appear from the top down and inside out along the growth direction of the nanorod, and finally form the tube structure. Actually, the nanotube with square hollow cross section consists of a mass of surrounded fine nanowires, which will be teared into independent ones at high temperature. When assembled into dye sensitized solar cells(DSSCs), the photoelectrical conversion efficiency of TiO2 nanotubes is much higher than that of nanorods, and the highest value(3.26%) is located at the etching temperature of 140 ℃. It could be deduced that the increased specific surface area and length shortening of the nanotube play the positive and negative effect on the photoelectrical property, respectively. Furthermore, the calcination effect on the structure and photovoltaic property of TiO2 nanotubes is also carried out. However, the fracture and aggregation of nanotubes could be observed after heating treatment, which therefore increase the difficulty of photo-induced carriers in directional transfer and also reduce the photoelectrical activity.