4x More Sensitive: UNIST's New MXene Sensor
Tracks Temp, Cough, and Pulse via Skin-Attachable Patch
South Korean researchers at UNIST have developed an ultra-sensitive MXene-based sensor material for skin-attachable patches that detect subtle physiological changes like temperature and pulse.
Professors Kim Soo-hyun and Kwon Soon-yong announced on April 11 that their titanium carbonitride MXene (Ti₃CNTz) offers 3x and 4x higher sensitivity to temperature and pressure, respectively, compared to conventional versions.
MXenes are advanced nanomaterials composed of layered atomic sheets of metal combined with carbon or nitrogen. Their thin, flexible, and highly conductive nature makes them a prime candidate for next-generation wearable sensors.
The specific MXene developed by the team (Ti₃CNTz) incorporates nitrogen, resulting in a sensitivity to temperature and pressure that is three and four times higher, respectively, than traditional nitrogen-free MXenes (Ti₃C₂Tx). This enhanced sensitivity allows the material to translate even the slightest physical stimuli into clear, distinct electrical signals.
The team achieved this performance leap by optimizing nitrogen concentrations within the material. The nitrogen atoms increase electron density in specific regions and amplify lattice vibrations, maximizing the sensor's responsiveness to external stimuli.
Furthermore, the researchers confirmed that the accordion-like structure of the MXene significantly bolsters its mechanical durability. These findings were validated through Density Functional Theory (DFT) calculations and Synchrotron-based X-ray Absorption Fine Structure (XAFS) analysis.
Practical applications of the sensor have already demonstrated remarkable results. It can distinguish subtle vocal cord vibrations--such as speaking, swallowing, or coughing--and capture real-time data including eye blinks and pulse waveforms at the wrist. When attached to the heel of a shoe, the sensor can even analyze gait patterns.
Beyond physical contact, the sensor is capable of non-contact temperature sensing from a distance of 1-2 mm, allowing it to detect infrared heat from a smartphone flash or sense ambient temperature changes as a finger approaches without touching.
“This is a transformative technology for next-generation human-machine interfaces and electronic skins for intelligent robots,” said Professor Kim Soo-hyun. “Its potential applications extend beyond healthcare into advanced nanoscience fields, including energy storage, catalysis, and electromagnetic interference shielding.”
The study was published online in Advanced Functional Materials on April 12.
