KAIST research team develops sensor to measure carbon dioxide concentration in exhaled breath. (Image courtesy of Yonhap)
DAEJEON, Feb. 11 (Korea Bizwire) — A research team at the Korea Advanced Institute of Science and Technology (KAIST) has developed a groundbreaking wearable sensor that can diagnose sleep health in real-time by measuring carbon dioxide levels in exhaled breath, the institute announced on February 10.
Traditional carbon dioxide sensors have been limited by their bulk and high power consumption. While photochemical carbon dioxide sensors – which measure changes in fluorescence intensity based on CO2 concentration – offer the advantage of miniaturization, researchers have struggled with long-term stability due to the photodegradation of dye molecules.
The KAIST team, led by Yoo Seunghyup, a professor at the School of Electrical Engineering, developed a low-power CO2 sensor by encasing an LED with a flexible thin-film organic photodiode. The device’s high optical efficiency allows for minimal light exposure to dye molecules. Its power consumption is just 171 μW (microwatts), several dozen times lower than conventional sensors that consume several milliwatts.
The researchers also identified the pathway of fluorescent molecule photodegradation, explaining why photochemical sensors develop increasing errors over time. They proposed an optical design method to reduce these errors.
Weighing just 0.12g and measuring 0.7mm in thickness, the sensor is light and thin enough to be attached inside a mask for CO2 measurements. It can operate continuously for up to 9 hours. The team noted that the device can even monitor respiratory rate by distinguishing between inhaled and exhaled breath in real-time.
“Our sensor possesses excellent characteristics including low power consumption, high stability, and flexibility, making it widely applicable in wearable devices,” Yoo said. “It could be used for the early diagnosis of various conditions, including chronic obstructive pulmonary disease and sleep apnea.”
The research findings were published in the online edition of the international journal “Device” on January 22.
Kevin Lee (kevinlee@koreabizwire.com)
