To use all functions of this page, please activate cookies in your browser.
With an accout for my.chemeurope.com you can always see everything at a glance – and you can configure your own website and individual newsletter.
- My watch list
- My saved searches
- My saved topics
- My newsletter
New technique controls crystalline structure of titanium dioxide
A new technique allows researchers to control the phase of the titanium dioxide by modifying the structure of the titanium trioxide and sapphire substrate.
02-07-2012: Researchers from North Carolina State University have developed a new technique for controlling the crystalline structure of titanium dioxide at room temperature. The development should make titanium dioxide more efficient in a range of applications, including photovoltaic cells, hydrogen production, antimicrobial coatings, smart sensors and optical communication technologies.
Titanium dioxide most commonly comes in one on of two major "phases," meaning that its atoms arrange themselves in one of two crystalline structures. These phases are "anatase" or "rutile." The arrangement of atoms dictates the material's optical, chemical and electronic properties. As a result, each phase has different characteristics. The anatase phase has characteristics that make it better suited for use as an antibacterial agent and for applications such as hydrogen production. The rutile phase is better suited for use in other applications, such as photovoltaic cells, smart sensors and optical communication technologies.
"Traditionally, it has been a challenge to stabilize titanium dioxide in the desired phase," says Dr. Jay Narayan, John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and co-author of a paper describing the work. "The material tends to transform into the anatase phase below 500 degrees Celsius [C], and transform into the rutile phase at temperatures above 500 C.
"We have now developed a technique that precisely controls the phase, or crystalline structure, of titanium dioxide at room temperature – and stabilizes that phase, so it won't change when the temperature fluctuates. This process, called phase tuning, allows us to fine-tune the structure of the titanium dioxide, so that it has the optimal structure for a desired application."
The process begins by using a widely available sapphire substrate that has the desired crystalline structure. Researchers then grow a template layer of titanium trioxide on the substrate. The structure of the titanium trioxide mimics the structure of the sapphire substrate. The titanium dioxide is then grown on top of the titanium trioxide template layer.
The structure of the titanium dioxide differs from the titanium trioxide – but is dictated by the structure of that template layer. This means that you can create the titanium dioxide in any phase, simply by modifying the structure of the titanium trioxide and sapphire substrate.
This works because of a process called domain matching epitaxy (DME). In DME, the lattice planes in the template layer line up with the lattice planes of the material being grown on that template. Lattice planes are the lines, or walls, which constitute a crystal.
The researchers have also demonstrated how this technique can be used with silicon computer chip substrates, which can be integrated into electronics such as smart sensors.
Domain epitaxy in TiO2/[alpha]-Al2O3 thin film heterostructures with Ti2O3 transient layer; Applied Physics Letters
This is where you can add this news to your personal favourites
- titanium dioxide
- North Carolina State Un…
- 1Drew Industrial Division of Ashland Specialty Chemical Company purchases industrial water-treatment business of London-based Fer
- 2LG-DOW Polycarbonate Plant Starts Production in Korea to Effectively Meet Regional Needs
- 3Allegra® Launched in Japan
- 4Caflon® surfactants from Univar as substitutes for banned nonylphenol ethoxylates
- 5Knoll AG: Pharma business sold for $6.9 billion:
- 6Plurafac LF 303 - Plurafac LF 305: The new generation of low-foam surfactants
- 7Honeywell Appoints Terrence Hahn as Vice President and General Manager for Fluorine Products
- 8Putting electronic cigarettes to the test
- 9Not just cars, but living organisms need antifreeze to survive
- 10Baytron P®– Gateway to a new generation of polymers