Nano-based Printed RFID Will Reduce the Cost of Printing TagsMarch 25, 2010
Cho, Tour and their teams reported in the journal a three-step process to print one-bit tags, including the antenna, electrodes and dielectric layers, on plastic foil. Cho's lab is working on 16-bit tags that would hold a more practical amount of information and be printable on paper as well.
Cho came across Tour's inks while spending a sabbatical at Rice in 2005. "Professor Tour first recommended we use single-walled carbon nanotubes for printing thin-film transistors," Cho said.
Tour's lab continues to support the project in an advisory role and occasionally hosts Cho's students. Tour said Rice owns half of the patent, still pending, upon which all of the technology is based. "Gyou-jin has carried the brunt of this, and it's his sole project," Tour said. "We are advisers and we still send him the raw materials" the single-walled carbon nanotubes produced at Rice.
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. "If there's no power source, there's no lifetime limit. When they receive the RF signal, they emit," Tour said.
Hurdles to commercialization
There are several hurdles to commercialization. First, the device must be reduced to the size of a bar code, about a third the size of the one reported in the paper, Tour said. Second, its range must increase.
"Right now, the emitter has to be pretty close to the tags, but it's getting farther all the time," he said. "The practical distance to have it ring up all the items in your shopping cart is a meter. But the ultimate would be to signal and get immediate response back from every item in your store - what's on the shelves, their dates, everything."
"At 300 meters, you're set - you have real-time information on every item in a warehouse. If something falls behind a shelf, you know about it. If a product is about to expire, you know to move it to the front - or to the bargain bin."
Tour allayed concerns about the fate of nanotubes in packaging. "The amount of nanotubes in an RFID tag is probably less than a picogram. That means you can produce one trillion of them from a gram of nanotubes - a miniscule amount. Our HiPco reactor produces a gram of nanotubes an hour, and that would be enough to handle every item in every Walmart."
"In fact, more nanotubes occur naturally in the environment, so it's not even fair to say the risk is minimal. It's infinitesimal."
Co-authors of the paper include Rice graduate student Ashley Leonard; Minhun Jung, Jinsoo Noh and Gwangyong Lee of Sunchon National University; and Jaeyoung Kim, Namsoo Lim, Chaemin Lim, Junseok Kim, Kyunghwan Jung and Hwiwon Kang of the Printed Electronics Research Center, Paru Corp., Sunchon, Korea.