Fiber-Shaped Temperature Sensor with High Seebeck Coefficient for Human Health and Safety Monitoring

Wearable thermoelectric (TE)-based temperature sensors capable of detecting and transmitting temperature data from the human body and environment show promise in intelligent medical systems, human-machine interfaces, and electronic skins. However, it has remained a challenge to fabricate the flexible temperature sensors with superior sensing performance, primarily due to the low Seebeck coefficient of the TE materials. Here, we report an inorganic amorphous TE material, Ge₅As₅₅Te₄₀, with a high Seebeck coefficient of 1050 μV/K, which is around 3 times higher than the organic TE materials and 2 times higher than the inorganic crystal TE materials. Due to the strong anticrystallization ability, the amorphous state of Ge₅As₅₅Te₄₀ can be well maintained during the thermal fiber-drawing process. The resulting TE fibers demonstrate superior temperature sensing properties, encompassing a broad working range (25-115 °C), a precise temperature resolution of 0.1 K, and a rapid response time of 5 s. Importantly, the TE properties of the fiber show high stability after repeated temperature variations between 5 and 10 K. Moreover, the fibers can be integrated into a mask and a wearable fabric for monitoring human respiratory rate and providing early warning for fire source proximity. These results highlight that the TE fiber with both natural flexibility and superior temperature sensing performance may find potential applications in wearable systems.