Whether palmtop, laptop or desktop, the basic idea layout of a computer has not changed for decades: the screen showing the data is separate from the chip processing the data. This could all change with the advent of new materials that can bring display and processing functions into intimate contact. These new materials are simultaneously semiconducting (like silicon chips) and transparent (like a display screen). This combination of properties is also needed in technologies such as LED’s, solar cells, smart windows and sensors.
Researchers at Tyndall National Institute, collaborating with partners in an EU-funded project called NATCO, have used their modelling and characterization expertise to develop a new material that is simultaneously semiconducting and transparent. In terms of its transparency across a wide range of wavelengths, the new Tyndall material is better than existing materials in its specific class of so-called p-type transparent conductive oxides (TCOs).
The new material was designed at Tyndall entirely through computer simulation, by initially simulating how different elements from the periodic table affect the transparency and conductivity of a known material, copper oxide. This approach yielded a set of design rules that were applied to other existing TCO materials in order to determine the optimum composition. Tyndall researcher Dr Michael Nolan explains the benefits of his in silico approach: “We ran hundreds of simulations, which took months to complete, but saved many years of trial and error in the laboratory.” The resulting new TCO material was barium-doped strontium copper oxide.
Tyndall’s proposed material composition was synthesised by Umicore, a leading materials company with headquarters in Belgium, which carefully prepared pellets to match this composition.
The new material was then processed and characterised by other members of the NATCO consortium. Partners Thales (France) and FORTH (Greece) then used lasers to skim material off the pellets and create thin films, as needed in a transparent electronic device. Finally, GeMac (France), FORTH and Tyndall measured the structural, optical and electrical characteristics of the films. An increase of transparency beyond visible light into the infra-red and ultra-violet was found, confirming the modelling predictions and showing that the rational approach to materials design was successful. The conductivity was found to be competitive with present p-type TCOs.
The project was funded by the EU’s “Future and Emerging Technology” programme and is an excellent example of the added value that can result from trans-european collaboration. The EU’s assessment of the project was “The NATCO project is thus something of a model of what a well-run European Union project can accomplish.” According to Tyndall project leader Dr Mircea Modreanu, “the great advantage of the EU funding model is that industrial partners are already in place in the project to take advantage of new discoveries. With the support of FP7 Ireland we are currently investigating a follow-on project to build on the success of NATCO“.