Sensors
with multifunctions have attracted great attention for their extensive
application value, among which humidity sensing and pressure sensing
are necessary to electronics undoubtedly because of the complex physical
environment we live in. Inspired by the structure of skin, in this
article, we design a new method to combine wrinkle structure with
porous sponge structure and achieve a novel, flexible, compressible,
and bifunctional sensor based on carbon nanotube–polydimethylsiloxane
(CNT–PDMS) with functions of humidity sensing and pressure
sensing. The performance of the humidity sensing part can be controlled
by the ultraviolet and ozone (UVO) treatment time and CNT concentration,
while the sensitivity of the pressure sensing part can be controlled
by the CNT concentration and grinding time of sugar granules. The
bifunctional sensor can easily sense approaching and touching of a
hand, which shows great potential of alarming and protecting some
electronics. Moreover, the bifunctional sensor can also be used in
detecting human joint motions and breath conditions as a wearable
and flexible health monitor.
We introduce a waterproof and stretchable triboelectric nanogenerator (TENG) that can be attached on the human body, such as fingers and the wrist, to harvest mechanical energy from body movement. The whole device is composed of stretchable material, making it able to endure diverse mechanical deformations and scavenge energy from them. Under gentle mechanical motions of pressing, stretching and bending, the device with an effective area of 1 × 2 cm2 can generate the peak-to-peak output current of 257.5 nA, 50.2 nA, and 33.5 nA, respectively. Besides, the TENG is tightly encapsulated, enabling it to avoid the influence of the external environment like humidity changes and harvest energy under water. Particularly, owing to the thin and soft properties of the encapsulation film, the device can respond to weak vibrations like the wrist pulse and act as a self-powered pulse sensor, which broadens its application prospects in the field of wearable energy harvesting devices and self-powered sensing systems.
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