RFID with semi-conductive carbon nanotube composite

Toray announced that it communicates wirelessly across the UHF (ultrahigh frequency) band with a printed semiconductor. This setup employs a printed radio-frequency identifier (RFID) that the company created. The RFID employs a high-performance semi-conductive carbon nanotube composite.

RFID with semi-conductive carbon nanotube composite

2 minutes, 60 secondes

Toray’s achievement demonstrated the potential for manufacturing UHF RFIDs by low-cost printing processes to dramatically streamline retail and logistics operations. Examples include automating cash registers and efficient inventory management. The company will accelerate development to commercialize printed RFIDs.

RFID should enhance work efficiency in retailing and logistics because it offers long-distance communication, batch reading, and other benefits. However, conventional silicon RFID tags have not become widespread because of their cost existing integrated circuit (IC) chips that are expensive, as they are made with complex processes employing high temperatures and vacuum environment. IC chip mounting processes are also needed. This situation drove efforts to manufacture low-cost ICs and mounting process-free printed semiconductors, such as organic semiconductors. The challenges over many years, however, have been a mobility of just 20 cm2/Vs which is far from application to UHF RFIDs.

Toray has engaged in R&D on RFIDs with printed materials, focusing on high-performance carbon nanotube composites. The semiconductor announced delivers a mobility of 182 cm2/Vs. While thin film transistors (TFTs) are either p-type (positively charged) or n-type (negatively charged), carbon nanotubes are normally p-type. Toray employed proprietary material technology to develop an n-type feature, realizing both p- and n-type TFTs that would be necessary to form power-saving, low-cost ICs.

The company fabricated an RFID prototype incorporating a 24-bit memory with a low-cost printing technology by adopting this new material and proprietary device and process technologies. It was thereby able to communicate wirelessly with UHF waves across a distance of 20 cm, becoming the first in the world as a printed UHF RFID. Toray’s product goal is to materialize a 60-bit memory. By popularizing its new low-cost coated RFIDs in retailing and logistics, it will be able to promote product data collection and sharing, dramatically enhancing overall supply chain efficiency.

The company will endeavor to improve communication performance, including communication distance, while developing on-film manufacturing technologies, in driving to commercialize printed RFIDs. Toray’s research in this area was supported in part by “Low Carbon Technology Research and Development Program” of Japan’s Ministry of the Environment.

Toray will combine its core polymer chemistry and nanotechnology to early establish printed RFID technology and thereby contribute streamline operations in the retailing and logistics fields, which is suffering from severe labor shortages. The company will endeavor to develop cutting-edge materials that can change our lives in keeping with its commitment, “contributing to society through the creation of new value with innovative ideas, technologies and products”.

UHF band
This frequency band is 860–960 MHz. Japan chose 920 MHz for UHF RFIDs. This band is widely used in a wide variety of mobile communication systems, particularly mobile phones and radios because it can transmit a lot of information and enables communication with compact antennas and transceivers. Other common applications include terrestrial digital televisions, airport surveillance radars, and electronic tags.

This is technology for using radio waves to contactlessly read and write information in RFID tags attached to products.

Carbon nanotube composites
Carbon nanotube compositesThese comprise carbon nanotubes, which is made of carbon atoms and has a diameter of nanometer order, and advanced semi-conductive polymers. It has been a challenge to disperse high-quality carbon nanotubes with high purity and uniform structures because of their strong aggregation nature. Toray was the first in the world to suppress aggregation of single-wall carbon nanotubes without inhibiting conductivity by attaching semi-conductive polymers on the surfaces of these nanotubes.

These electronic circuits comprise diodes, resistors, wiring, and other components, and have functions such as process and record information. Most electronic devices and systems, including computers, radio equipment, appliances, and automobiles, incorporate such circuits.

This indicates the mobility of holes, electrons in semiconductors. High mobility ensures fast responses. Another benefit is that TFTs can be shrunk, aiding miniaturization.

More information www.toray.com