Long-Range Hexagonal Arrangement of TiO2 Nanotubes by Soft Lithography-Guided Anodization

Optimized Spacing between TiO2 Nanotubes for Enhanced Light Harvesting and Charge Transfer

“…Different from the as‐formed NTs, the concentration of C1s and F1s drastically reduces due to the decomposition of fluoride‐ and carbon‐rich layers during heat treatment, see Figure S3 and S5 in the Supporting Information. In line with the literature,,, the atomic concentration of C and F become lower throughout the tubular layers. Spaced NTs show a slightly higher fluoride content, which can be due to the utilization of fluoride‐rich electrolyte during anodization.…”

Ideally Hexagonally Ordered TiO2 Nanotube Arrays

“…This can be observed for the anodization of the sunflower pattern where, already after 5 min, the nanotube bottoms are not as perfectly ordered, as seen from the top views. Recently, Vega et al . received long‐range‐ordered nanotubular TiO 2 structures by using laser interference lithography to pre‐texture the Ti foils before anodization.…”

“…The cross section shown in Figure c depicts a TiO 2 nanotube layer thickness of approximately 2 μm. Compared to the literature, these are the thickest and, at the same time, ideally hexagonally ordered TiO 2 nanotube layers obtained to date.…”

“…This can be observed fort he anodization of the sunflower pattern [24] where,a lready after 5min, the nanotube bottoms are not as perfectly ordered, as seen from the top views. Recently, Vega et al [26] received long-range-ordered nanotubular TiO 2 structures by using laser interference lithography to pre-texture the Ti foils before anodization. However,f or this method, three different resists and four different etching steps were employed for the fabrication of the pattern,m aking the method rather complicated.…”

“…Furthermore, nanotube layers thinnert han 1 mmw ere achieved. Even though these most recentp apers [21][22][23][24][25][26] represent as ignificant advancementi nt he state-of-the-art in terms of TiO 2 nanotube ordering, all published scanning electron microscopy (SEM) images clearly display an umber of point defects within the nanotube ordering (voids, heptagons, pentagons, etc.). In addition, all published patterns in these papers were smaller than 10 10 mm 2 .…”