Researchers speed up organic semiconductors

Speeds approaching inorganic equivalents

A single crystal of the new organic semiconductor material shown in polarized light. is approximately twice as fast as the parent organic material from which it was derived. The white scale bar at the bottom center of the photo represents 10 microns or 10 millionths of a meter. (Credit: Anatoliy Sokolov)

A team of researchers from Harvard and Stanford University have come up with a new organic semiconductor that could potentially rival inorganic semiconductors, according to an article in the journal Nature Communications.

Up until now organic semiconductors have been very flexible, but at the same time too slow for things like displays. On the other hand inorganic semiconductors such as silicon are faster, but inflexible.

The search for new inorganic semiconductor have been mostly hit and miss trials, but now researchers have come up with faster method of developing and refining the organic semiconductors using massive computational techniques combined with synthesis.

The researchers used DNTT, already known to be a good organic semiconductor, as their starting point, then considered various compounds possessing chemical and electrical properties that seemed likely to enhance the parent material’s performance if they were attached.

Using the expected chemical and structural properties of the modified materials, researchers from Harvard University predicted that two of the seven candidates would most readily accept a charge. They calculated that one of the two was markedly faster than the other and from their analysis they estimated that the material would be about twice as fast as the parent material.

For comparison, the new material is more than 30 times faster than the amorphous silicon currently used for liquid crystal displays in products such as flat panel televisions and computer monitors.

A single crystal of the new organic semiconductor material shown in polarized light. is approximately twice as fast as the parent organic material from which it was derived. The white scale bar at the bottom center of the photo represents 10 microns or 10 millionths of a meter. (Credit: Anatoliy Sokolov)

“It would have taken several years to both synthesize and characterize all the seven candidate compounds. With this approach, we were able to focus on the most promising candidate with the best performance, as predicted by theory,” Zhenan Bao, Associate Professor of Chemical Engineering at Stanford University. says.  “This is a rare example of truly rational design of new high performance materials.”

It took about a year and a half to perfect the synthesis of the new compound and make enough of it to test, Anatoliy Sokolov, postdoctoral researcher at Stanford says.

“Our final yield from what we produced was something like 3 percent usable material and then we still had to purify it.”

“Synthesizing some of these compounds can take years,” says Anatoliy Sokolov, postdoctoral researcher working in the lab of Zhenan Bao, associate professor of chemical engineering at Stanford University. “It is not a simple thing to do.”

The researchers hope their predictive approach can serve as a blueprint for other research groups working to find a better material for organic semiconductors.S|A

The following two tabs change content below.