Nanocrystals enable faster, more flexible electronics

The work, led by doctoral student David Kim, was published in the journal Nature Communications.

‘We have a performance benchmark in amorphous silicon, which is the material that runs the display in your laptop, among other devices,’ said team member Prof Cherie Kagan in a statement. ’Here, we show that these cadmium selenide nanocrystal devices can move electrons 22 times faster than in amorphous silicon.’

Besides speed, another advantage cadmium selenide nanocrystals have over amorphous silicon is the temperature at which they are deposited. Whereas amorphous silicon uses a process that operates at several hundred degrees, cadmium selenide nanocrystals can be deposited at room temperature and annealed at mild temperatures.

Another innovation that allowed the researchers to use flexible plastic was their choice of ligands, the chemical chains that extend from the nanocrystals’ surfaces and help facilitate conductivity as they are packed together into a film. 

‘There have been a lot of electron transport studies on cadmium selenide, but until recently we haven’t been able to get good performance out of them,’ Kim said. ‘The new aspect of our research was that we used ligands that we can translate very easily onto the flexible plastic; other ligands are so caustic that the plastic actually melts.’