This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
This Small Business Technology Transfer (STTR) Phase II project focuses on developing a commercially viable process for producing a versatile passive radio frequency identification (RFID) tag. Existing passive tag technologies have many limitations that hinder their widespread use. The most significant limitations include minimal operating range, high unit costs, and a rigid form that makes the tag difficult to adhere to curved or irregularly shaped surfaces. This project aims to overcome these limitations by utilizing two innovative technologies. The first technology is a new type of field-effect transistor (FET) that is fabricated from high-purity and semiconducting-enriched single-walled carbon nanotube (SWCNT) solutions. These innovative FETs provide improvements in operating frequency and current-carrying capacity which enable an extended RFID range. The second innovation is a high-speed, highly accurate, and ultrafine-dimension-capable system for depositing electrical components and antennas onto flexible substrates at or near room temperature. This project aims to culminate in the production and evaluation of prototype carbon nanotube-based RFID tags that meet the value-added needs of the RFID marketplace.
The broader impact/commercial potential of this project will be the development of low-cost, flexible, and extended-range RFID tags. These tags will provide industry and the U.S. Government with a reliable and economic methodology for managing and tracking supply chain inventory, will allow an expansion in the use of smart cards, and will enable the identifying and tracking of animals and marine life, a critical element in protecting endangered species. The results of the project will also improve applications such as passive radio frequency identification (RFID) tags, flexible electronics, IR-invisible antennas, and embedded IR sensing, imaging, and communications.
Brewer Science, Inc., with its project partners, University of Massachusetts-Lowell (UML) and Checkpoint Systems, worked to develop a flexible and extended-range passive radio-frequency identification (RFID) tag that is free from the limitations of the existing passive tag technologies. Existing passive tag technologies suffer from many drawbacks such as minimal operating range, high unit costs, and unit non-flexibility. Brewer Science and its partners have two innovative approaches to overcome these limitations. The first is to develop new-generation printable semiconducting and conductive carbon nanotube (CNT) ink materials that can be used to fabricate RFID tags. CNTs possess many unique characteristics such as high current-carrying capacity, high operating speed, high mobility, flexibility, and compatibility with cost-effective printing processes. The second approach is a high-speed, highly accurate, and ultrafine-dimension-capable RFID tag printing system for printing these RFID tags onto flexible substrates at or near room temperature. Project Outcomes or Findings The project objectives were two-fold: (a) to develop superior printable semiconducting and conductive CNT materials for RFID tags, and (b) to print flexible RFID tags with extended range using the developed CNT materials. Brewer Science successfully developed stable, ultrahigh-purity, water-based semiconducting single-walled CNT dispersions that are needed to make efficient field-effect transistor (FET) components for RFID tags. The metal impurity in these dispersions was less than 300 parts per billon, which is better than the targeted value. In addition, Brewer Science developed several ink-jet-, aerosol-jet-, and screen-printable conductive CNT inks that can be used to print various components of the RFID tags, such as antenna, capacitor, interconnect, rectifier, and CNT FETs, and successfully printed them on flexible substrates. Besides developing the CNT inks, Brewer Science also developed the in-house capability to fabricate entire RFID tags. Brewer Science demonstrated fully printed flexible transistors, which are major components of the RFID tags, on flexible substrates by using both aerosol-jet and ink-jet printing technologies. These transistors had ON/OFF ratios up to 103. It is worthy to note that in phase I of the NSF program, Brewer Science and its working partners had already demonstrated transistors with an operating speed of 5 Gigahertz, which is an important factor to improve the RFID working range. Some other components of the RFID tags, such as rectangular LC antennas and a full-wave rectifier, were also designed, printed successfully on a flexible Kapton substrate, and tested for their functionality. Brewer Science presented this work at the RFID Europe 2011 conference, and attracted much attention from the audience that include many large RFID manufacturers. Brewer Science possesses a unique combination of expertise in developing CNT inks for RFID tags as well as RFID printing capability. Even after the end of the project, Brewer Science is committed to develop better CNT inks for RFID tags and to develop a flexible RFID prototype. This work will have a major impact in many areas that use RFID tags, such as supply chain inventory, smart cards, postal services, health care, consumer goods, the automotive industry, IR sensing, animal and marine life identification and tracking, etc. In addition, Brewer Science’s CNT inks will have a huge impact in other areas of applications in which CNTs can be used as new-generation, better-performing materials, such as sensors, conductive traces, displays, nano-electronics, etc. So far, Brewer Science has already sampled many semiconducting and conductive CNT inks to potential customers in various areas of applications. And the effort to develop and commercialize CNT ink products is continuous. Products that have resulted from the award (collections, data sets, software, educational materials) NSF Phase II project resulted the following products: 1. Two papers in peer reviewed journals, and one conference proceeding. 2. A presentation in RFID Europe 2011 Conference. Title: "Long-range CNT-based Flexible RFID Tags". 3. An electro-hydrodynamic Jet (E-Jet) flexible RFID circuit printer station at UML. 4. A RFID testing system at UML. Additional information None.
