Laser direct writing of Ga2O3/liquid metal-based flexible humidity sensors

• Published in: Opto-Electronic Advances Vol. 6; no. 7; pp. 27 - 36
• Main Authors: Songya Cui, Yuyao Lu, Depeng Kong, Huayu Luo, Liang Peng, Geng Yang, Huayong Yang, Kaichen Xu
• Format: Journal Article
• Language: English
• Published: State Key Laboratory of Fluid Power and Mechatronic Systems,School of Mechanical Engineering,Zhejiang University,Hangzhou 310030,China 01.07.2023; School of Information and Electrical Engineering,Hangzhou City University,Hangzhou 310015,China.%State Key Laboratory of Fluid Power and Mechatronic Systems,School of Mechanical Engineering,Zhejiang University,Hangzhou 310030,China%School of Information and Electrical Engineering,Hangzhou City University,Hangzhou 310015,China; Institue of Optics and Electronics, Chinese Academy of Sciences
• Subjects: flexible electronics; humidity sensors; laser direct writing; liquid metal; wearable sensors; flexible electronics; wearable sensors; humidity sensors; liquid metal; laser direct writing
• ISSN: 2096-4579
• DOI: 10.29026/oea.2023.220172

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 re-mains 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 humid-ity,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.