Optimized porous rutile TiO2 nanorod arrays for enhancing the efficiency of dye-sensitized solar cells

Abstract

Highly ordered rutile TiO 2 nanorod arrays (NRAs) are promising architectures in dye-sensitized solar cells (DSCs). However, the efficiency of DSCs based on such photoanodes is still relatively low, largely due to the limited internal surface area. Herein, we report that highly oriented rutile TiO 2 NRAs with film thickness up to $30 mm was developed by a facile hydrothermal method. More importantly, an optimized porous rutile TiO 2 NRAs with a large internal surface area was fabricated on the FTO (fluorine-doped tin oxide) substrate via a secondary hydrothermal treatment and when applied as the photoanodes in DSCs, a record efficiency of 7.91% was achieved. Broader contextOne-dimensional (1-D) single-crystalline rutile TiO 2 nanorod arrays (NRAs) have attracted much attention in various applications due to its unique optoelectronic properties, such as sensors, photocatalysts, electrochromism, ultraviolet photodetectors, solar water splitting, self-cleaning coatings and solar cells. In general, a large surface area is of great signicance in most of its applications that require sufficient reaction sites on the surface of TiO 2 . In our present work, we provide a facile hydrothermal method for preparation of rutile TiO 2 NRAs with a high surface area. Our strategies focused on developing thicker rutile TiO 2 NRAs by proper treatment of the FTO substrates and adopting a hydrothermal etching route for further enhancing its surface area. The selective etching route introduced in our work may become a general method for developing other wide-band semiconductor nanorod/nanotube materials (e.g. ZnO, Nb 2 O 5 , SnO 2 and TiO 2 with other crystal phases) with a large surface area, which would be highly benecial for their applications in solar water splitting, photocatalysts or dyesensitized solar cells. Moreover, such a material provided in this report (i.e. 1-D single-crystalline rutile TiO 2 NRAs) may nd its promising applications in the related energy and environmental applications due to its well-dened porous array structure and large surface area.

Maximizing omnidirectional light harvesting in metal oxide hyperbranched array architectures

“…Another classical solution is to decorate the 1D nanostructures with dendritic NR branches [21][22][23] . For example, several studies regarding long NWs or the assembly of 1D nanostructures into three-dimensional (3D) hierarchical tree-like or bush-like branched NW structures have been reported [24][25][26][27][28][29] . In this regard, the enhancement of surface area is still restricted along either the axial or ambient directions.…”

Dye‐Sensitized Solar Cells with Vertically Aligned TiO2 Nanowire Arrays Grown on Carbon Fibers

“…[9] To further improve device performance, more accurate control on TNW morphology, structure, purity, composition, and surface/interface properties is required. Besides, more efficient photoactive and hole-transport layers are desirable.…”

One-Dimensional TiO2 Nanostructured Photoanodes: From Dye-Sensitised Solar Cells to Perovskite Solar Cells

“…Although the modification of the 1D nanostructures can contribute to improving the light utilisation in solar cells, the backside-illumination condition still limits the overall light harvesting efficiency so that the frontside-illumination condition is more preferable to enhance the overall photovoltaic performances of the cells. As shown in Figure 12b, Lv and co-workers [49] applied porous rutile TiO 2 NR arrays onto TCO substrates for enhancing the performance of DSCs, where~30 µm thick TiO 2 NR arrays were prepared by a hydrothermal method, and the completed NR arrays were further etched by HCl. The etched TiO 2 NR arrays showed much higher dye loading compared to their counterpart mesoporous TiO 2 , leading to an improved PCE of 7.91% with J sc of 20.49 mA·cm −2 .…”