Toray achieves world’s first UHF wireless communication with low-cost printed RFIDs


Toray Industries, Inc. (Tokyo, Japan) has recently become the first in the world to communicate 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. 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 commercialise printed RFIDs.

RFID should greatly 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 the cost of 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 20cm2/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 now delivers a mobility of 182cm2/Vs—a new world record. 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, realising 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 20cm, becoming the first in the world as a printed UHF RFID. Toray’s product goal is to materialise a 60-bit memory. By popularising 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 endeavour to improve communication performance, including communication distance, while developing on-film manufacturing technologies, in driving to commercialise printed RFIDs. Toray’s research in this area was supported in part by the “Low Carbon Technology Research and Development Programme” of Japan’s Ministry of the Environment.

Toray will combine its core polymer chemistry and nanotechnology to establish printed RFID technology early and thereby contribute to streamlining operations in the retailing and logistics fields, which are suffering from severe labour shortages.

Caption: Carbon nanotube composites comprise of carbon nanotubes, which are made of carbon atoms and have a diameter in the nanometre order, and advanced semi-conductive polymers (photo: Toray)

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