MoS₂-Decorated Laser-Induced Graphene for a Highly Sensitive, Hysteresis-free, and Reliable Piezoresistive Strain Sensor

Abstract

Advancement of sensing systems, soft robotics, and point-of-care testing requires the development of highly efficient, scalable, and cost-effective physical sensors with competitive and attractive features such as high sensitivity, reliability, and preferably reversible sensing behaviors. This study reports a highly sensitive and reliable piezoresistive strain sensor fabricated by one-step carbonization of the MoS2-coated polyimide film to obtain MoS2-decorated laser-induced graphene. The resulting three-dimensional porous graphene nanoflakes decorated with MoS2 exhibit stable electrical properties yielding a reliable output for longer strain/release cycles. The sensor demonstrates high sensitivity (i.e., gauge factor, GF ≈1242), is hysteresis-free (∼2.75%), and has a wide working range (up to 37.5%), ultralow detection limit (0.025%), fast relaxation time (∼0.17 s), and a highly stable and reproducible response over multiple test cycles (>12 000) with excellent switching response. Owing to the outstanding performances of the sensor, it is possible to successfully detect various subtle movements ranging from phonation, eye-blinking, and wrist pulse to large human-motion-induced deformations.

Black Phosphorus@Laser‐Engraved Graphene Heterostructure‐Based Temperature–Strain Hybridized Sensor for Electronic‐Skin Applications

“…The linear resistance profile with laser parameters such as engraving power, scan line, and raster speed were optimized (see Figure S2, Supporting Information) in our previous report. [ 15 ] To achieve high stretchability, elastic recovery, high cycling stability, and solution processability, we introduced polystyrene‐ block ‐poly(ethylene‐ ran ‐butylene)‐ block ‐polystyrene (SEBS) as a substrate material for BP@LEG composite. As a functional material, poly(allylamine) passivated BP and LEG composite material was used.…”

“…The mechanism can be linearized for a longer range by introducing bridging material, as reported in our previous study. [ 15 ] We reported on a piezoresistive strain sensor that exploited MoS 2 as the bridging material in a simple layout that can detect the strain only.…”

Wearable Flexible Strain Sensor Based on Three-Dimensional Wavy Laser-Induced Graphene and Silicone Rubber

“…The resistance response was stable and nearly linear under the lower strain loading. Since fewer cracks were grown, and the interspaces between graphene flakes dominated the variation in resistance under a lower strain loading [28]. Therefore, the steady response range of the wavy-LIG sensor was 0-31.8% and the planar-LIG sensor was 0-40.4%.…”

“…Due to the excellent mechanical performance and high conductivity, laser-induced graphene (LIG) is the ideal material to prepare a strain sensor [ 25 , 26 , 27 , 28 ]. LIG can be synthesized with a CO infrared laser to scan on the polyimide (PI) film in the air, which is a one-step synthesis.…”

Laser-Induced Graphene: En Route to Smart Sensing

“…For example, Luo et al found that the laser conditions dictating the morphology and structure of LIG had great effect on piezoelectric sensor's performance, and the optimized LIG sensor showed higher gauge sensitivity than commercial strain gauge by nearly 10 times [75]. Chhetry and co-workers designed a MoS 2 /LIG strain sensor for the detection of voice, eye-blinking, and pulse wave [76]. The decoration of MoS 2 significantly reduced the crack in LIG and improved the mechanical strength of the sensor.…”