A Flexible Humidity Sensor with Wide Range, High Linearity, and Fast Response Based on Ultralong Na₂Ti₃O₇ Nanowires

A flexible humidity sensor with wide sensing range, superior sensitivity, high linearity, and advanced response/recovery capabilities is extremely desirable for practical applications in human body-related (HBR) monitoring and human-machine interaction (HMI). However, the practical sensor lacks a versatile nanomaterial integrated with sensing capabilities and mechanical flexibility to meet the criteria. Herein, a comprehensive flexible humidity sensor with ultralong Na₂Ti₃O₇ nanowires (>120 μm) is subtly constructed for the first time. Owing to the distinguish nanowires network structure, the sensor exhibits wide sensing range (11-95% RH), high sensitivity (>10³), high linearity (R² > 0.98), and fast response/recovery capability (8.9/2.1 s), as well as excellent respiratory stability (>5000 s). In addition, the Na₂Ti₃O₇-based humidity sensor demonstrates superior flexibility and antibacteria capabilities, and exhibits diverse applications in respiration monitoring, noncontact detection, as well as dynamic interactive display. This work provides a multifunctional humidity sensor with excellent practicability, suggesting the great potential in next-generation human-related flexible/wearable devices.