The proliferation of radio-frequency identification (RFID) devices over the past decade has been nothing short of remarkable. But one of the most sweeping promises of the RFID revolution—that the devices will replace the ubiquitous bar code—has not yet come to pass because of their cost. So researchers have been striving to build RFIDs from a cheaper material: plastic.

In 2005 a group of engineers at IMEC, a company based in Leuven, Belgium, overcame a major hurdle by constructing a diode made of pentacene, an organic compound that has semiconducting properties. Prior to IMEC's breakthrough, organic devices were considered too slow to power RFID chips. The next step came early this year when a group led by Eugenio Cantatore of Philips Research Laboratories in Eindhoven, the Netherlands, announced that it had built a fully functional RFID tag made entirely of plastic electronics. Such a chip would be simpler to manufacture than a silicon-based tag because the design could be directly printed onto a plastic substrate. The elimination of complex assembly may pave the way for low-cost RFID tags incorporated into product packaging. And because RFID readers have a range of a few meters, supermarket clerks could speed the checkout process by scanning all the contents of a grocery cart at once.

Meanwhile engineers at Hewlett-Packard Laboratories have devised a miniature wireless chip that could eventually replace RFID tags in many applications. Called the Memory Spot (below), the chip can hold up to four megabits of flash memory and transfer those data to a reader at 10 megabits a second. It could be embedded into passports, postcards, pharmaceutical labels and hospital wristbands.