Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Tiny Step Edges, Big Step for Surface Science


Experiments at the Vienna University of Technology can explain the behaviour of electrons at tiny step edges on titanium oxide surfaces. This is important for solar cell technology and novel, more effective catalysts.

It can be found in toothpaste, solar cells, and it is useful for chemical catalysts: titanium dioxide (TiO2) is an extremely versatile material. Alhough it is used for so many different applications, the behaviour of titanium oxide surfaces still surprises.

Tiny step edges on titanium oxide surfaces

Jiri Pavelec, Gareth Parkinson, Benjamin Daniel, Martin Setvin (left to right)

Professor Ulrike Diebold and her team at the Vienna University of Technology managed to find out why oxygen atoms attach so well to tiny step edges at titanium oxide surfaces. Electrons accumulate precisely at these edges, allowing the oxygen atoms to connect more strongly. In solar cells, this effect should be avoided, but for catalysts this can be highly desirable.

Microscope Pictures of Titanium Oxide Surfaces

Titanium oxide is Ulrike Diebold’s favourite material. In her latest publication, she and her team studied the behaviour of titanium oxide surfaces using scanning tunnelling microscopy and atomic force microscopy.

Titanium oxide can be used for solar cells. In the so-called Graetzel cell, an inexpensive but inefficient type of solar cell, it plays the central role. “In a solar cell, we want electrons to move freely and not attach to a particular atom”, says Martin Setvin, first author of the publication, which has now appeared in the journal “Angewandte”.

The opposite is true for catalysts: For catalytic processes, it is often important that electrons attach to surface atoms. Only at places where such an additional electron is located can oxygen molecules attach to the titanium oxide surface and then take part in chemical reactions.

Electrons Distort the Crystal Structure

Usually, it takes a considerable amount of energy to have the electrons bond to a particular atom. “When an electron is localized at a titanium atom, the electric charge of the atom is changed, and due to electrostatic forces, the titanium oxide crystal is distorted”, says Ulrike Diebold. To create this lattice distortion, energy has to be invested – and therefore this effect does not usually occur by itself.

However, the surface of titanium oxide is never completely flat. On a microscopic scale, there are tiny steps and edges, many of them with a height of only one atomic layer. At these edges, electrons can localize quite easily. The atoms at the edge only have neighbours on one side, and therefore no major lattice distortions are created when these atoms receive an additional electron and change their charge state. “We have observed that oxygen molecules can connect to the surface precisely at these locations”, says Diebold.

Better Solar Cells, More Efficient Catalysts
Important conclusions for technology can be drawn from this: for photovoltaics, such step edges should be avoided, for catalysts this newly discovered effect yields great opportunities. Surfaces could be microstructured to exhibit many such edges, making them extremely effective catalysts.

Original Publication

Further Information:

Prof. Ulrike Diebold
Institute of Applied Physics
Vienna University of Technology
Wiedner Hauptstraße 8
M: +43-664-605883467

Martin Setvin, PhD
Institute of Applied Physics
Vienna University of Technology
Wiedner Hauptstraße 8
T: +43-1-58801-13470

Florian Aigner | EurekAlert!
Further information:

Further reports about: Atoms Cells Microscope Physics Surface TiO2 Titanium crystal structure oxygen molecule titanium titanium oxide

More articles from Life Sciences:

nachricht Signaling Pathways to the Nucleus
19.03.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht In monogamous species, a compatible partner is more important than an ornamented one
19.03.2018 | Max-Planck-Institut für Ornithologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

A new kind of quantum bits in two dimensions

19.03.2018 | Physics and Astronomy

Scientists have a new way to gauge the growth of nanowires

19.03.2018 | Materials Sciences

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Science & Research
Overview of more VideoLinks >>>