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Atomically Defined Templates for Epitaxial Growth of Complex Oxide Thin Films
Published on: December 4, 2014
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Coalescence-Driven Verticality in Mesoporous TiO2 Thin Films with Long-Range Ordering.
Victor Malgras1, Yasuhiro Shirai2, Toshiaki Takei3
1International Center for Young Scientists, National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan.
Journal of the American Chemical Society
|August 14, 2020
Summary
Researchers created highly interconnected, vertically porous titanium dioxide (TiO2) films using block copolymer self-assembly. This novel structure enhances surface area for improved charge and photon interactions in advanced applications.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Engineering
Background:
- Mesoporous semiconducting films require continuous interconnectivity and minimal tortuosity for optimal surface area at heterojunctions.
- Traditional lithography struggles to create nanostructures below 50 nm with desired porosity.
- Soft-templating and lyotropic crystal engineering offer alternative routes to ordered porous materials.
Purpose of the Study:
- To develop a method for creating mesoporous titanium dioxide (TiO2) films with continuously perpendicular pores.
- To achieve long-range ordering and interconnected vertical porosity in TiO2 films.
- To demonstrate the potential of these films for advanced functional applications.
Main Methods:
- Utilizing a polystyrene-b-poly(ethylene oxide) block copolymer in a three-solvent system.
- Employing lyotropic crystal engineering to self-assemble a body-centered cubic (Im3̅m) template.
- Analyzing the resulting TiO2 film structure for pore interconnectivity and vertical orientation.
Main Results:
- Self-assembly yielded a body-centered cubic (Im3̅m) template with long-range 3D periodicity.
- Vertical contraction led to the formation of coalesced, orthogonal channels with strong interconnectivity.
- Demonstrated lateral long-range ordering and continuous transverse vertical porosity in the TiO2 material.
Conclusions:
- The study successfully fabricated TiO2 films with highly ordered, interconnected vertical porosity.
- This nanostructure is ideal for maximizing surface area and charge/photon interactions.
- The films show promise for applications in filtration, sensing, catalysis, optoelectronics, and hosting perovskite nanocrystals.
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