Influence of substrates and rutile seed layers on the assembly of hydrothermally grown rutile TiO 2 nanorod arrays

Kalb, Julian; Dorman, James; Folger, Alena; Gerigk, Melanie; Knittel, Vanessa; Plüisch, Claudia Simone; Trepka, Bastian; Lehr, Daniela; Chua, Emily J.; Wittemann, Alexander; Scheu, Christina; Polarz, Sebastian; Schmidt‐Mende, Lukas

doi:10.1016/j.jcrysgro.2018.05.004

Cited by 11 publications

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“…As the nanofinger growth proceeds, the diameter decreases by approximately 5%. This is attributed to changing process parameters such as temperature and precursor concentration during the growth process [35,39]. The decrease in diameter causes cracks in the film as shown in the inset of Figure 1A.…”

Section: Resultsmentioning

confidence: 99%

Controlling the Spatial Direction of Hydrothermally Grown Rutile TiO2 Nanocrystals by the Orientation of Seed Crystals

et al. 2019

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Hydrothermally grown TiO2 nanorods are a key material for several electronic applications. Due to its anisotropic crystal structure, the electronic properties of this semiconductor depend on the crystallographic direction. Consequently, it is important to control the crystal orientation to optimize charge carrier pathways. So far, the growth on common polycrystalline films such as fluorine tin oxide (FTO) results in randomly distributed growth directions. In this paper, we demonstrate the ability to control the growth direction of rutile TiO2 nanocrystals via the orientation of the seed crystals. The control of the orientation of such nanocrystals is an important tool to adjust the electronic, mechanical, and chemical properties of nanocrystalline films. We show that each employed macroscopic seed crystal provides the growth of parallel nanofingers along the [001] direction under specific angles. The parallel growth of these nanofingers leads to mesocrystalline films whose thickness and surface structure depends on the crystal orientation of the seed crystal. In particular, the structure of the films is closely linked with the known inner structure of hydrothermally grown rutile TiO2 nanorods on FTO. Additionally, comprehensive 1D structures on macroscopic single-crystals are generated by branching processes. These branched nanocrystals form expanded 2D defect planes, which provide the opportunity of defect doping-induced two-dimensional electronic systems (2DES).

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Section: Resultsmentioning

confidence: 99%

Controlling the Spatial Direction of Hydrothermally Grown Rutile TiO2 Nanocrystals by the Orientation of Seed Crystals

et al. 2019

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“…The ART process is based on nucleation and growth, which depends on many variables such as the sample preparation method, heat flow, and dopants . For the anatase/rutile mixture, the larger portion (17.63 wt.%) dopant rutile is likely to contribute to the crystallization of rutile, which results in greater rutile generation. On the other hand, a small portion of dopant (2.4 wt% WO 3 ) and with the small percentage resulting rutile portion (2.92%) it is hard to tell if WO 3 contributed significantly to the ART.…”

Section: Resultsmentioning

confidence: 99%

TiO₂ based nanopowder coatings over stainless steel plates for UV‐C photocatalytic degradation of methylene blue

et al. 2019

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Immobilizing the photocatalyst in a water treatment process design is essential; however, the immobilization method may affect the photoactivity of the photocatalyst. In this work, photocatalyst powders were successfully coated on 316 L stainless steel plates by a novel brush coating method. Three combinations of photocatalyst mixtures (pure TiO 2 anatase, anatase doped with WO 3 , or TiO 2 rutile) were and annealed at different temperatures between 460-540 C. The~10 μm thick coatings demonstrated full plate coverage and strong adhesion and adequate durability. Surface roughness increased with annealing temperature. The doping and annealing process enabled band gap reduction to the visible light spectrum for all coatings, with the smallest band gap being 2.48 eV (1 eV = 1.6 × 10 −19 J). Subsequent methylene blue degradation tests under UV-C showed that the coatings annealed in 460 C exhibited the best performance and with the highest degradation rate constant of 5.59 hours −1 . K E Y W O R D Sadvanced oxidation process, annealing, band gap, photocatalyst coatings, roughness

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“…In case of conventional electron-beam lithography, titanium was deposited on a patterned electron resist. After removing the mask, the titanium was oxidized at 850 °C resulting in polycrystalline rutile seeds along the pattern lines as we described previously [36]. The seed grains have diameters between 5 and 100 nm and hence, their dimensions are similar to those of the nanorods.…”

Section: Resultsmentioning

confidence: 99%

“…The aluminium was dissolved in a 0.5 molar NaOH bath within 12 s. The samples were developed in methyl isobutyl ketone (MIBK) for 25 s and cleaned with isopropanol. In case of electron-beam lithography, a polycrystalline rutile TiO 2 films was fabricated as a seed layer for the hydrothermal growth process as we described in detail in our previous work [36]. For that purpose, a 40 nm thin titanium layer was deposited via electron-beam assisted evaporation from titanium pellets (99.995% purity, Kurt J. Lesker Ltd.) at a pressure of 1 .…”

Section: Methodsmentioning

confidence: 99%

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Advanced scanning probe lithography using anatase-to-rutile transition to create localized TiO₂ nanorods

Kalb

Knittel

Schmidt‐Mende

2019

Beilstein J. Nanotechnol.

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In this article, we demonstrate the position-controlled hydrothermal growth of rutile TiO2 nanorods using a new scanning probe lithography method in which a silicon tip, commonly used for atomic force microscopy, was pulled across an anatase TiO2 film. This process scratches the film causing tiny anatase TiO2 nanoparticles to form on the surface. According to previous reports, these anatase particles convert into rutile nanocrystals and provide the growth of rutile TiO2 nanorods in well-defined areas. Due to the small tip radius, the resolution of this method is excellent and the method is quite inexpensive compared to electron-beam lithography and similar methods providing a position-controlled growth of semiconducting TiO2 nanostructures.

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Influence of substrates and rutile seed layers on the assembly of hydrothermally grown rutile TiO 2 nanorod arrays

Cited by 11 publications

References 91 publications

Controlling the Spatial Direction of Hydrothermally Grown Rutile TiO2 Nanocrystals by the Orientation of Seed Crystals

Controlling the Spatial Direction of Hydrothermally Grown Rutile TiO2 Nanocrystals by the Orientation of Seed Crystals

TiO₂ based nanopowder coatings over stainless steel plates for UV‐C photocatalytic degradation of methylene blue

Advanced scanning probe lithography using anatase-to-rutile transition to create localized TiO₂ nanorods

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Influence of substrates and rutile seed layers on the assembly of hydrothermally grown rutile TiO 2 nanorod arrays

Cited by 11 publications

References 91 publications

Controlling the Spatial Direction of Hydrothermally Grown Rutile TiO2 Nanocrystals by the Orientation of Seed Crystals

Controlling the Spatial Direction of Hydrothermally Grown Rutile TiO2 Nanocrystals by the Orientation of Seed Crystals

TiO2 based nanopowder coatings over stainless steel plates for UV‐C photocatalytic degradation of methylene blue

Advanced scanning probe lithography using anatase-to-rutile transition to create localized TiO2 nanorods

Contact Info

Product

Resources

About

TiO₂ based nanopowder coatings over stainless steel plates for UV‐C photocatalytic degradation of methylene blue

Advanced scanning probe lithography using anatase-to-rutile transition to create localized TiO₂ nanorods