Boffins perfect technique for building light-emitting flexible semi-conductor

November 14th, 2007 - 1:55 am ICT by admin  
The research team led by George G. Malliaras, associate professor of materials science and engineering, had long studied the molecular semiconductor ruthenium tris-bipyridine.

For many reasons, including its ability to allow electrons and holes (spaces where electrons were before they moved) to pass through it easily, the material has the potential to be used for flexible light-emitting devices.

Sensing, microscopy and flat-panel displays are among its possible applications.

As part of their research, the team fabricated a device out of the ruthenium metal complex that was spin-coated onto an insulating substrate with pre-patterned gold electrodes.

The scientists used electron force microscopy to measure directly the electric field of the device.

Prof. Malliaras said the key was to understand the fundamental physics of the material - that is, what happened when it encountered an electric field, both at the interfaces and inside the film.

The researchers discovered that it was at the interfaces - two gold metal electrodes sandwiching the ruthenium complex film - where the electric field was created.

“When you apply the electric field, ions in the material move about, and that creates the electric fields at the interfaces,” said Prof. Malliaras.

He said their research was a huge step forward in knowing how to build and engineer future devices, adding that essential to the effort was the ability to pattern the ruthenium complex using photolithography, a technique not normally used with such materials and one that took the researchers more than three years to perfect, using the knowledge of experts in nanofabrication, materials and chemistry.

The research appears in the Sept. 30 online publication of the journal Nature Materials. (ANI)

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