The challenges involved in realizing
next-generation applications,
like robotics, artificial electronic skin, noninvasive healthcare
monitoring, motion detection, and so forth, enabled with wireless
human-machine interfaces, present a growing need for high-performance
flexible and wearable multifunctional electromechanical sensors. In
this regard, emerging classes of two-dimensional nanomaterials and
their hybrids show excellent promise as active sensing materials,
given their high flexibility and remarkable sensitivity to external
pressure and strain. This report is the first demonstration of SnS/Ti3C2T
x
nanohybrid-based
electromechanical sensors for use in applications like sign-to-text
translation and sitting posture analysis. The as-fabricated piezoresistive
sensor exhibits a high gauge factor and sensitivity value, that is,
7.41 and 7.49 kPa–1, respectively. Furthermore,
the nanohybrid-based sensor displayed a negligible change in performance
over ∼3500 and ∼2500 cycles for both pressure and strain
characterizations, indicating high robustness and exceptional stability.
The underlying intrinsic piezoresistive mechanism in layered nanomaterials
and the Ohmic contact formed at the SnS/Ti3C2T
x
heterojunction are explained in detail
with the help of energy band diagrams wherein the work function and
the E
homo values are extracted experimentally
by ultraviolet photoelectron spectroscopy for both SnS and Ti3C2T
x
. The successful
demonstration of sign-to-text translation and e-cushion applications
using SnS/Ti3C2T
x
nanohybrid-based piezoresistive sensors will further expand the
scope of flexible and wearable electronics research.
This report demonstrates the fabrication
and development
of a tellurium
nanowire (TeNW) and MXene (Ti3C2T
x
) nanohybrid-based pressure sensor. The fabricated
sensor was later encapsulated in poly(dimethylsiloxane) (PDMS) and
used as buttons for the communication system to demonstrate a personal
safety application using Morse code. The fabricated pressure sensor
demonstrated an excellent sensitivity of 9.29241 kPa–1 and stability withstanding over ∼3000 cycles of applied pressure
(∼1.729 kPa). Real-time ultraviolet photoelectron spectroscopy
(UPS) is utilized for realizing the band diagram of the TeNWs/Ti3C2T
x
nanohybrid to
understand the transport of charge carriers upon external pressure.
The transduction mechanism of the fabricated pressure sensor is explained
using the improved intrinsic piezoresistive properties of the MXene
and TeNWs in TeNWs/Ti3C2T
x
, which helps in increasing the tunneling current by a decrease
in the effective interlayer resistance/interwire tunneling distance
of the nanohybrid. Further, an Android application was created to
wirelessly receive data via Bluetooth from the sensors
connected to a microcontroller. The application displayed the pattern
pressed on the sensors as a Morse dash or dot. This can further be
used in a similar fashion to that of a telegraph to send complex messages
such as “HELP”. Developing a TeNWS/Ti3C2T
x
nanohybrid-based
flexible sensor opens many possible wireless monitoring and communication
applications.
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