Scientists have presented a new way to transform metal into thin and bendable films. They are used in a variety of electronic devices.
The researchers noted that many metals and their compounds need to be turned into thin films, which are often used in technological products such as electronics, displays, fuel cells or catalysts. However, some metals are more difficult to turn into films – platinum, iridium, ruthenium, tungsten. First of all, this happens because they require a very high temperature to evaporate – usually more than 2 thousand degrees Celsius.
Typically, scientists synthesize films of these metals using techniques such as sputtering and electron beam evaporation. The latter method consists in melting and evaporating metals at high temperatures, after which a film forms on the plates. However, traditional methods are very expensive, consume a lot of energy, and can be unsafe due to high voltages.
Now researchers at the University of Minnesota have developed a way to vaporize these metals at significantly lower temperatures – less than 200 degrees Celsius. By developing and adding organic ligands to metals – combinations of carbon, hydrogen and oxygen atoms – the researchers were able to significantly increase the vapor pressure in the materials, making them easier to vaporize at lower temperatures. Their new methodology is not only simpler, but also allows for higher quality materials that are easily scaled.
These metals are used to make a variety of products, from semiconductors for computer applications to display technology. Platinum, for example, is also an excellent catalyst for energy conversion and storage and is being considered for use in many devices.
“Cost reduction will play a large role in both industry and research,” said William Nunn, a graduate student in chemical engineering and materials science at the University of Minnesota. “We now hope to see renewed interest in more complex materials that contain these refractory metals.”