0D to 2D carbon-based materials in flexible strain sensors: recent advances and perspectives

Abstract

In the past decade, flexible strain sensors have attracted much attention in the fields of health care, soft robots and other flexible electronics due to their unique flexibility, high stability, and strong mechanical properties. To further meet the requirements of the excellent performance for electronic equipment, carbon-based conductive sensitive materials have become one of the first choice for the preparation of flexible strain sensors due to their excellent electrical conductivity, mechanical properties, and high compatibility. Herein, based on different strain behaviors, this paper analyzes the working mechanism of tensile and compressive strain sensors, focusing on the latest research progress of carbon-based conductive materials in strain sensors with different dimensions. The applications of carbon-based sensitive materials with multifunctional strain sensing in the areas of physiological information detection, human motion, human-machine interaction, and visual display have also been summarized. Furthermore, it has been attempted to discuss the current challenges of carbon-based strain sensors as well as the prospect of flexible strain sensors. This review is aimed to provide appropriate references for further exploitation of multi-functional flexible carbon-based strain sensors.

B, P, and S heteroatom doped, bio- and hemo-compatible 2D graphitic-carbon nitride (g-C3N4) with antioxidant, light-induced antibacterial, and bioimaging endeavors

“…The carbon materials such as carbon nanotubes (CNTs), graphene oxide (GO), graphene quantum dots (GQDs), and carbon-based fullerenes, as well as their allotropic phases e.g. amorphous carbon, graphite, and diamonds, carbon-based materials have become valuable in biomedical, sensing and environmental applications [3][4][5]. The unique characteristics that each member of the carbon family possesses have led to specific use of these materials in a variety of biological applications, including as biosensing, drug transport, tissue engineering, imaging, cancer therapy, and diagnostics and treatment [6][7][8][9].…”

Liquid Metal and Carbon Nanofiber-Based Strain Sensor for Monitoring Gesture, Voice, and Physiological Signals

“…Soft and stretchable strain sensors, as one of the important elements in the family of wearable sensors, , have undergone development from traditional wire and/or foil strain gauges − to ultrathin-film-state strain sensors, for the purpose of making them respond simultaneously to the epidermic changes , and realizing precise detection . In addition, numerous contributions have been made to strain sensors by the use of newly developed materials, such as low-dimensional carbon materials, , biomass, , metal nanowires, , MXene fabric, , as well as hydrogels , and composites loaded with nanoconductive fillers, as well as the recently proposed crack-based strain sensors by imitating slit sensilla of arthropods . The optimizations of stretchable electronic materials and their layout to construct elastic and conductive networks are the key points in the studies of soft strain sensors. , For example, the micro crack-junctions’ disconnection–reconnection of a 20 nm film on a viscoelastic polymer can contribute to the ultrahigh gauge factor (GF = 2000); meanwhile, the zigzag crack structure on flexible and interlaced graphene ribbons was demonstrated to improve sensitivity. , The main idea in crack-based strain sensors is focused on how to make the conductive layer split and coalesce by integrating ductile metals (such as Au, Ag, and Cu) and viscoelastic polymers [such as poly­(urethane acrylate) (PUA) and poly­(ethylene terephthalate) (PET)].…”

“…1 Soft and stretchable strain sensors, as one of the important elements in the family of wearable sensors, 2,3 have undergone development from traditional wire and/or foil strain gauges 4−6 to ultrathin-film-state strain sensors, 7 for the purpose of making them respond simultaneously to the epidermic changes 8,9 and realizing precise detection. 10 In addition, numerous contributions have been made to strain sensors by the use of newly developed materials, such as lowdimensional carbon materials, 11,12 biomass, 13,14 metal nanowires, 15,16 MXene fabric, 17,18 as well as hydrogels 19,20 and composites 21 loaded with nanoconductive fillers, as well as the recently proposed crack-based strain sensors by imitating slit sensilla of arthropods. 22 The optimizations of stretchable electronic materials and their layout to construct elastic and conductive networks are the key points in the studies of soft strain sensors.…”

Superhydrophobic and Highly Elastic Strain‐Sensing Fiber Embedded with Carbon Nanotubes and Aerogels Based on the Dipping and Drying Method

“…[21][22][23][24][25] This enables the fiber itself to act as a sensor rather than mounting the sensor on the fiber material, maximizing the advantages of flexible fibers. [26][27][28][29][30][31] For instance, a slight increase in the strain of the fiber can rapidly change the resistance and rate of change of resistance of the conductive fiber, facilitating the recognition of movement at each bending angle of a joint. In the case of highly elastic fibers, the rapid recovery can be used to continuously and accurately detect swift movement changes.…”