Hydrothermal Etching Treatment to Rutile TiO sub(2) Nanorod Arrays for Improving the Efficiency of CdS-Sensitized TiO sub(2) Solar Cells

• Published in: Nanoscale research letters 2016-12, Vol.11 (1), p.1-9
• Main Authors: Wan, Jingshu, Liu, Rong, Tong, Yuzhu, Chen, Shuhuang, Hu, Yunxia, Wang, Baoyuan, Xu, Yang, Wang, Hao
• Format: Article
• Language: English
• Subjects: Arrays; Etching; Nanostructure; Photovoltaic cells; Quantum dots; Solar cells; Specific surface; Titanium dioxide
• ISSN: 1931-7573; 1556-276X
• DOI: 10.1186/s11671-016-1236-9

Highly ordered TiO sub(2) nanorod arrays (NRAs) were directly grown on an F:SnO sub(2) (FTO) substrate without any seed layer by hydrothermal route. For a larger surface area, the second-step hydrothermal treatment in hydrochloric acid was carried out to the as-prepared TiO sub(2) NRAs. The results showed that the center portion of the TiO sub(2) nanorods were dissolved in the etching solution to form a nanocave at the initial etching process. As the etching time extended, the tip parts of the nanocave wall split into lots of nanowires with a reduced diameter, giving rise to a remarkable increase of specific surface area for the TiO sub(2) NRAs. The TiO sub(2) films after etching treatment were sensitized by CdS quantum dots (QDs) to fabricate quantum dot-sensitized solar cells (QDSSCs), which exhibited a significant improvement in the photocurrent density in comparison with that of the un-treated device, this mainly attributed to the enhancement of QD loading and diffused reflectance ability. Through modifying the etching TiO sub(2) films with TiCl sub(4), a relatively high power conversion efficiency (PCE) of 3.14 % was obtained after optimizing the etching time.