Discover Osaka University researchers’ breakthrough in optical sensor technology: a soft, bendable, and wireless sensor made with carbon nanotubes and organic transistors on ultra-thin polymer film.
The researchers from the Institute of Scientific and Industrial Research (SANKEN) at Osaka University have unveiled a development in the field of optical sensors. They have created a soft, flexible, and wireless optical sensor by utilizing carbon nanotubes and organic transistors on an ultra-thin polymer film. This innovative sensor is capable of bending without breaking and can even function after being crumpled into a ball.
The sensor’s design marks a departure from conventional optical sensors, which are typically made using rigid inorganic semiconductors and ferroelectric materials. Instead, the team has employed an array of carbon nanotube photodetectors printed on the polymer substrate. These nanotubes heat up when exposed to light, creating a thermal gradient that generates a voltage signal. The sensitivity of the nanotubes is enhanced by doping them with chemical carriers during the printing process. This allows the sensor to detect not only visible light but also infrared light, which is associated with heat or molecular vibrations.
A key feature of this sensor is its integration with wireless technology. Organic transistors printed on the same polymer substrate organize the voltage signals into an image signal. This signal can be transmitted wirelessly to a computer using a Bluetooth module, eliminating the need for physical wired connections. The research team has successfully built a prototype of this sheet-type optical sensor and demonstrated its ability to sense heat from various objects, such as human fingers and wires, as well as the flow of glucose through tubes.
The sensor has shown high sensitivity across a wide range of wavelengths and good bending durability, maintaining functionality even after being crumpled. The unique properties of this wireless, flexible optical sensor hold great potential for a variety of applications, including non-destructive imaging, wearable devices, and soft robotics. It offers a new and simpler way to perform tasks such as evaluating the quality of liquids without the need for sampling.
Reference: “Ultraflexible Wireless Imager Integrated with Organic Circuits for Broadband Infrared Thermal Analysis” by Rei Kawabata, Kou Li, Teppei Araki, Mihoko Akiyama, Kaho Sugimachi, Nozomi Matsuoka, Norika Takahashi, Daiki Sakai, Yuto Matsuzaki, Ryo Koshimizu, Minami Yamamoto, Leo Takai, Ryoga Odawara, Takaaki Abe, Shintaro Izumi, Naoko Kurihira, Takafumi Uemura, Yukio Kawano and Tsuyoshi Sekitani, 11 January 2024, Advanced Materials.
DOI: 10.1002/adma.202309864
