A research team at UNIST has developed a highly sensitive MXene-based sensor material capable of attaching to the skin to simultaneously detect minute biosignals such as body temperature, pulse, and cough. As it can read changes in temperature and pressure together, its potential applications in wearable healthcare, electronic skin, and human-machine interfaces have been suggested.

A research team led by Professors Su-Hyun Kim and Soon-Yong Kwon of the UNIST Graduate School of Semiconductor Materials and Components announced on the 11th that they have developed a titanium carbonitride-based MXene material capable of detecting both temperature and pressure changes.

MXene is a nanomaterial in which metals are bonded to carbon or nitrogen in a layered structure. It is thin, flexible, and has high electrical conductivity, so it has been studied as a material for wearable devices and healthcare sensors.

The material developed by the research team is a nitrogen-containing titanium carbonitride MXene. Compared to existing carbide-based MXenes, its sensitivity to temperature changes has increased by approximately three times, and its sensitivity to pressure stimulation has increased by more than four times. The explanation is that even small stimuli cause significant changes in electrical resistance, enabling the conversion of biological signals into more distinct electrical signals.

Performance improvement was achieved through nitrogen concentration control. The research team controlled electron density and lattice vibration characteristics by finding the optimal nitrogen concentration, thereby enhancing responsiveness to external stimuli. This principle was confirmed through density functional theory calculations and synchrotron-based X-ray absorption microstructure analysis.

In the experiment, sensors attached to the neck distinguished subtle vocal cord movements associated with speaking, swallowing, and coughing. Eye blinking was measured in real-time around the eyes, pulse waveforms at the wrists, and it was also possible to analyze walking patterns by attaching sensors to the heels of shoes.

Non-contact temperature sensing performance was also confirmed. The sensor detected infrared heat from a smartphone camera flash at a distance of 1 to 2 mm and recognized temperature changes upon approach even without direct contact with a finger.

Professor Kim Su-hyeon explained that this research could lead to next-generation human-machine interfaces and intelligent robotic electronic skin technology, as it enables precise simultaneous detection of temperature and pressure while controlling signal interference. He also stated that the scope of application could be expanded beyond healthcare to advanced nanomaterial fields such as energy storage, catalysts, and electromagnetic shielding.

The results of this research were published online on April 12 in the materials science journal *Advanced Functional Materials*. The research was conducted with support from the Ministry of Science and ICT, the National Research Foundation of Korea, and the InnoCore project.