Measurements of an individual’s water metabolism
dynamical information can provide us rich biological
information in a noninvasive way. This concept is hindered by
the trade-off between the sensitivity and responsive velocity of
traditional moisture sensors. Herein, inspired by the molecular
detecting system based on weak bond interactions in natural
organisms, we designed a new concept of a tunable graphenepolymer
heterogeneous nanosensing junction by confining a
reasonable thickness sensing material into graphene nanochannels.
The fundamentally new sensing mechanism based
on dynamical hydrogen bonds endows the sensor with over 4
orders of magnitude sensitivity toward a wide range of relative
humidity (RH) (from 0% to 97%) with unprecedented fast
response (20 ms) and recovery times (17 ms) with little humidity hysteresis. The promising advantages of the sensor allow us to
record humidity fluctuation information in real time during a user’s speech and breath, which can both reveal the speech feature
and monitor the respiration rate accurately. Importantly, this advanced sensor provides a new opportunity for accurate and
reliable physiological and psychological monitoring by detecting the subtlest RH fluctuations on human skin in a noncontact
way.