(Peer-Reviewed) Laser direct writing of Ga₂O₃/liquid metal-based flexible humidity sensors
Songya Cui 崔颂雅 ¹ ², Yuyao Lu 陆雨姚 ¹, Depeng Kong 孔德朋 ¹, Huayu Luo 罗华昱 ¹, Liang Peng 彭亮 ², Geng Yang 杨赓 ¹, Huayong Yang 杨华勇 ¹, Kaichen Xu 徐凯臣 ¹
¹ State Key Laboratory of Fluid Power and Mechatronic Systems, School of Mechanical Engineering, Zhejiang University, Hangzhou 310030, China
中国 杭州 浙江大学机械工程学院 流体动力与机电系统国家重点实验室
² School of Information and Electrical Engineering, Hangzhou City University, Hangzhou 310015, China
中国 杭州 浙大城市学院 信息与电气工程学院
Flexible and wearable humidity sensors play a vital role in daily point-of-care diagnosis and noncontact human-machine interactions. However, achieving a facile and high-speed fabrication approach to realizing flexible humidity sensors remains a challenge. In this work, a wearable capacitive-type Ga₂O₃/liquid metal-based humidity sensor is demonstrated by a one-step laser direct writing technique.
Owing to the photothermal effect of laser, the Ga₂O₃-wrapped liquid metal particles can be selectively sintered and converted from insulative to conductive traces with a resistivity of 0.19 Ω·cm, while the untreated regions serve as active sensing layers in response to moisture changes. Under 95% relative humidity, the humidity sensor displays a highly stable performance along with rapid response and recover time.
Utilizing these superior properties, the Ga₂O₃/liquid metal-based humidity sensor is able to monitor human respiration rate, as well as skin moisture of the palm under different physiological states for healthcare monitoring.