Last week at the spring meeting of the Materials Research Society in San Francisco, I sat down with Plastic Logic’s co-founder and chief scientist, Henning Sirringhaus to talk about the company’s R&D efforts. In January they announced the details of their e-reader, called the Que, the first consumer product that uses organic transistors, but did not say when it will be on the market. Now Plastic Logic is looking to the next generation of devices that could be made to support a video display.
In my discussion with Sirrinhgaus, I asked to see some of his slides to help me understand the materials science behind his work, he pulled out his Que. It’s remarkably thin and lightweight–benefits that come from driving the display with organic transistors on a plastic backing, rather than a glass-backed amorphous-silicon transistor array. As with any device that uses the reflective displays made by E Ink, the picture was crisp black and white with no glare from the overhead lights.
I haven’t gotten my hands on Technology Review’s iPad, which is being tested at our Cambridge, MA-based office and is reportedly not changing anyone’s life (watch the video review.) I suspect for reading a document or book in the California sunshine, I would rather use the Que, which has a reflective display. But one thing Plastic Logic’s reader can’t do right now, which the iPad can with a conventional display, is show color or video. However, that may soon be changing.
Sirringhaus, who in addition to his position at Plastic Logic is a professor of electron device physics at the University of Cambridge, says that his group has developed transistor arrays that switch fast enough to drive a video display. The company might have to make some trade-offs in the future, with regard to color. Reflective displays are nice to look at, but systems that use filters to create a color image lose a lot of light in the process, which means battery drain. Organic LEDs are another option, but they’re not ready for production yet, says Sirringhaus.
On the basic science side, Sirringhaus says the biggest remaining problem in organic electronics is that the physics of the molecules used to make them simply aren’t very well understood yet. Ideally the materials scientists would tell the chemists exactly how to tweak these molecules in order to make them pack into perfect structures that transport charge well and make fast-switching transistors and efficient solar cells. But right now it’s not possible to design in that way. Sirringhaus didn’t go so far as to say Plastic Logic got lucky, and the company is not divulging which molecules it uses to make its transistors. But, he told me, making a high-performance semiconducting polymer is still “a matter of luck”.