How plastics promise a computing revolution

"You start thinking about this polymer and you start thinking that you can create batteries everywhere out of it," Palmore said. "You could wrap cell phones in it or electronic devices. Conceivably, you could even make it into fabric."

Better batteries might be one solution, but surely a better one is to remove the need for batteries completely. This is the aim of Massachusetts-based Konarka Technology, developers of Plastic Power technology that converts light into electrical power.

Of course photocells are by no means new, but conventionally they are bulky, heavy, fragile and expensive to manufacturer, both in terms of raw material and in energy consumption. However, according to Konarka, plastic photocells are the answer.

"Power Plastic is inexpensive – five times less than traditional solar; lightweight – 25 to 50 grams per square metre; versatile – it can be coloured, patterned and cut-to-fit; and flexible – so it can be adapted to an application's form factor."

However, applications like providing power for PDAs, mobile phones, digital cameras, personal music players and laptops – all of which the company claim will operate under artificial light as well as direct sunlight – is just the start, as we'll see later.

Logic circuitry

Plastics then, are capable of providing us with screens that offer features not available with silicon, and they also show great potential in powering our mobile devices, but what about logic circuitry? What advances have plastics made here?

To date, much of the research into plastic logic circuits has been for applications that require ultra-low cost rather than performance. We're thinking here of circuits – including logic and radio electronics – that are so cheap that they can be incorporated into the packaging of clothes and groceries. They're used mainly for RFID (Radio Frequency Identification) – a high-tech version of barcodes that can be read from a distance.

Impressive as it might be to create RFID tags that will transit 64 bits of data wirelessly by printing special plastics onto the packaging of groceries, we're not talking about the sort of memory and processors you might find in a PC. And in this area, relatively little has been reported.

Epson have demonstrated an eight-bit flexible processor running at just 500KHz but even this used amorphous silicon printed onto the plastic substrate rather than genuine plastic circuitry. So why has plastic electronics made so few inroads into this fundamental area? We asked Dr Neil Greenham, Reader in Physics at the University of Cambridge.

"Plastic transistors are a lot slower than the silicon transistors in a Pentium," he admitted. "The 'mobility' is the key figure. It's a measure of how fast the electrons move in an electric field, and it's low because the electrons have to jump between polymer chains to be transported through a solid film. It allows us to build circuits operating at hundreds of kilohertz, but we're never going to compete with a Pentium operating at gigahertz. Of course, we're still trying to improve the performance of our transistors, partly by making them smaller, but also by changing the chemical structure of the polymers so that neighbouring chains pack more closely together in a regular structure."

Pervasive Electronics

According to some experts, the plastic revolution could have a far more wide-ranging influence. We know that plastic electronics might end up in our clothes and packaging, and that displays could be so large and cheap that they might replace billboards, but perhaps the most innovative potential applications relate to the building industry.

Today, silicon solar panels are costly, so it's still rare to see them fitted to the roofs of houses. Konarka Technology sees all that changing thanks to their low-cost plastic photocells. As prices continue to tumble, Konarka envisage that we'll see them totally covering roofs and other architectural elements. In a report prepared for the US Department of Energy, Universal Display Corporation introduces the intriguing concept of electronic windows.