Nano-based RFID tags may soon make long lines at store checkouts history

Washington, Mar 20 : Those never-ending lines at store checkouts could soon be history, thanks to radio-frequency identification (RFID) tags printed through a new roll-to-roll process that could replace bar codes and make checking out of a store a snap.

Rice University researchers, in collaboration with a team led by Gyou-jin Cho at Sunchon National University in Korea, have come up with an inexpensive, printable transmitter that can be invisibly embedded in packaging.

It would allow a customer to walk a cart full of groceries or other goods past a scanner on the way to the car; the scanner would read all items in the cart at once, total them up and charge the customer''s account while adjusting the store''s inventory.

More advanced versions could collect all the information about the contents of a store in an instant, letting a retailer know where every package is at any time.

The technology is based on a carbon-nanotube-infused ink for ink-jet printers first developed in the Rice lab of James Tour. The ink is used to make thin-film transistors, a key element in RFID tags that can be printed on paper or plastic.

"We are going to a society where RFID is a key player," said Cho.

The researchers are developing the electronics as well as the roll-to-roll printing process that will bring the cost of printing the tags down to a penny apiece and make them ubiquitous, he said.

Already, RFID tags are almost everywhere—the tiny electronic transmitters are used to identify and track products and farm animals. They''re in passports, library books and devices that let drivers pass through tollbooths without digging for change.

The researchers described a three-step process to print one-bit tags, including the antenna, electrodes and dielectric layers, on plastic foil.

They are now working on 16-bit tags that would hold a more practical amount of information and be printable on paper as well.

Printable RFIDs are practical because they''re passive. The tags power up when hit by radio waves at the right frequency and return the information they contain.

The study has been published in the latest issue of the journal IEEE Transactions on Electron Devices.