An improved wearable, stretchable gas sensor using nanocomposites

Date:
August 28, 2020
Source:
Penn State
Summary:
A stretchable, wearable gas sensor for environmental sensing has
been developed and tested.



FULL STORY ==========================================================================
A stretchable, wearable gas sensor for environmental sensing has been
developed and tested by researchers at Penn State, Northeastern University
and five universities in China.


==========================================================================
The sensor combines a newly developed laser-induced graphene foam material
with a unique form of molybdenum disulfide and reduced-graphene oxide nanocomposites. The researchers were interested in seeing how different morphologies, or shapes, of the gas-sensitive nanocomposites affect the sensitivity of the material to detecting nitrogen dioxide molecules at
very low concentration. To change the morphology, they packed a container
with very finely ground salt crystals.

Nitrogen dioxide is a noxious gas emitted by vehicles that can irritate
the lungs at low concentrations and lead to disease and death at high concentrations.

When the researchers added molybdenum disulfide and reduced graphene
oxide precursors to the canister, the nanocomposites formed structures
in the small spaces between the salt crystals. They tried this with a
variety of different salt sizes and tested the sensitivity on conventional interdigitated electrodes, as well as the newly developed laser-induced graphene platform.

When the salt was removed by dissolving in water, the researchers
determined that the smallest salt crystals enabled the most sensitive
sensor.

"We have done the testing to 1 part per million and lower concentrations,
which could be 10 times better than conventional design," says
Huanyu Larry Cheng, assistant professor of engineering science and
mechanics and materials science and engineering. "This is a rather
modest complexity compared to the best conventional technology which
requires high-resolution lithography in a cleanroom." Ning Yi and
Han Li, doctoral students at Penn State and co-authors on the paper
in Materials Today Physics, added, "The paper investigated the sensing performance of the reduced graphene oxide/moly disulfide composite. More importantly, we find a way to enhance the sensitivity and signal-to-noise
ratio of the gas sensor by controlling the morphology of the composite
material and the configuration of the sensor-testing platform. We think
the stretchable nitrogen dioxide gas sensor may find applications in
real-time environmental monitoring or the healthcare industry."

========================================================================== Story Source: Materials provided by Penn_State. Original written by Walt
Mills. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Ning Yi, Zheng Cheng, Han Li, Li Yang, Jia Zhu, Xiaoqi Zheng,
Yong Chen,
Zhendong Liu, Hongli Zhu, Huanyu Cheng. Stretchable,
Ultrasensitive, and Low-Temperature NO2 Sensors based on rGO/MoS2
Nanocomposites. Materials Today Physics, 2020; 100265 DOI:
10.1016/j.mtphys.2020.100265 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200828081052.htm

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