This method could pave the way for new classes of electronic devices, such as ultrathin wearable sensors, flexible transistors and computing elements, and highly sensitive and compact imaging devices. As a demonstration, the team fabricated a thin membrane of pyroelectric material — a class of heat-sensing material that produces an electric current in response to changes in temperature. The thinner the pyroelectric material, the better it is at sensing subtle thermal variations.
Fabricating the Thinnest Pyroelectric Membrane
With their new method, the team fabricated the thinnest pyroelectric membrane yet, measuring 10 nanometres thick, and demonstrated that the film is highly sensitive to heat and radiation across the far-infrared spectrum. The newly developed film could enable lighter, more portable, and highly accurate far-infrared (IR) sensing devices, with potential applications for night-vision eyewear and autonomous driving in foggy conditions.
Advancements in Thermal Sensing and Applications
Current state-of-the-art far-IR sensors require bulky cooling elements. In contrast, the new pyroelectric thin film requires no cooling and is sensitive to much smaller changes in temperature. The researchers are exploring ways to incorporate the film into lighter, higher-precision night-vision glasses. "This film considerably reduces weight and cost, making it lightweight, portable, and easier to integrate," Xinyuan Zhang, a graduate student in MIT’s Department of Materials Science and Engineering (DMSE), said. "For example, it could be directly worn on glasses."
Potential for Broader Applications of Ultrathin Electronic Films
The heat-sensing film could also have applications in environmental and biological sensing, as well as imaging of astrophysical phenomena that emit far-infrared radiation. The new lift-off technique is generalisable beyond pyroelectric materials. The researchers plan to apply the method to make other ultrathin, high-performance semiconducting films.
