Recent Advances in Carbon Material‐Based Multifunctional Sensors and Their Applications in Electronic Skin Systems

Abstract

Electronic skin (e‐skin) is driving significant advances in flexible electronics as it holds great promise in health monitoring, human–machine interfaces, soft robotics, and so on. Flexible sensors that can detect various stimuli or have multiple properties play an indispensable role in e‐skin. Despite tremendous research efforts devoted to flexible sensors with excellent performance regarding a certain sensing mode or property, emerging e‐skin demands multifunctional flexible sensors to be endowed with the skin‐like capability and beyond. Considering outstanding superiorities of electrical conductivity, chemical stability, and ease of functionalization, carbon materials are adopted to implement multifunctional flexible sensors. In this review, the latest advances of carbon‐based multifunctional flexible sensors with regard to the types of detection modes and abundant properties are introduced. The corresponding preparation process, device structure, sensing mechanism, obtained performance, and intriguing applications are highlighted. Furthermore, diverse e‐skin systems by integrating current cutting‐edge technologies (e.g., data acquisition and transmission, neuromorphic technology, and artificial intelligence) with carbon‐based multifunctional flexible sensors are systematically investigated in detail. Finally, the existing problems and future developing directions are also proposed.

Interfacially Locked Metal Aerogel Inside Porous Polymer Composite for Sensitive and Durable Flexible Piezoresistive Sensors

“…The comprehensive performance especially the stability of the Ag 2 Au 3 AG/MS/PDMS op piezoresistive flexible pressure sensor is among the top when compared with those metal based ones reported in literature (Table S1 , Supporting Information). Even when compared with those based on other sensing materials, [ 2 , 8 ] the Ag 2 Au 3 AG/MS/PDMS op flexible pressure sensor can distinguish itself as well.…”

“…[ 2c‐e ] Alternative strategy of dipping or coating conductive materials (such as metal particles, [ 3 ] metal nanowires, [ 4 ] carbon nanotubes, [ 5 ] graphene, [ 6 ] and MXene [ 7 ] ) on the insulating porous elastic matrixes (such as Thermoplastic polyurethanes (TPU), polyurethane (PU), and porous PDMS) has been developed to fabricate flexible piezoresistive pressure sensor. [ 4 , 8 ] Generally, flexible pressure sensors based on porous elastic substrates with excellent mechanical stability are supposed to have good durability. [ 9 ] However, the strength of the interfacial interaction seriously affects the performance of the flexible sensor.…”

Bio‐Based Piezo‐ and Thermoresistive Photocurable Sensing Materials from Acrylated Epoxidized Soybean Oil

“…[32] With respect to nanofillers for the processing of smart polymer composites, carbon-based materials, namely carbon nanotubes, carbon black or graphene oxide, are particularly suitable for developing multifunctional sensing materials, as they present thermal stability, low toxicity, flexibility and high electrical and thermal conductivities. [33,34] Polymer-based composites containing carbonaceous materials have been widely used in applications such as temperature, humidity, pressure or deformation sensors. [35] In particular, different functional systems and devices have been prepared based on piezoresistive and thermoresistive materials obtained by the combination of carbon-based fillers and different thermoplastic polymers, [36,37] at the point that the use of carbonaceous materials in combination with photocurable systems have been extended to 3D printing [38] or even 4D printing.…”

Revolution in Flexible Wearable Electronics for Temperature and Pressure Monitoring—A Review

“…Despite significant research efforts devoted to flexible sensors with good performance in a specific detecting mode or attribute, growing e-skin requires multifunctional flexible sensors with skin-like capabilities and beyond. Carbon materials are used to develop multifunctional flexible sensors because of their great electrical conductivity, chemical stability, and simplicity of functionalization [41]. (b) Photograph of the manufactured pressure-sensitive graphene FETs, Scale bar, 1 cm [28].…”