Flexible and Stretchable Pressure Sensors: From Basic Principles to State-of-the-Art Applications

Abstract

Flexible and stretchable electronics have emerged as highly promising technologies for the next generation of electronic devices. These advancements offer numerous advantages, such as flexibility, biocompatibility, bio-integrated circuits, and light weight, enabling new possibilities in diverse applications, including e-textiles, smart lenses, healthcare technologies, smart manufacturing, consumer electronics, and smart wearable devices. In recent years, significant attention has been devoted to flexible and stretchable pressure sensors due to their potential integration with medical and healthcare devices for monitoring human activity and biological signals, such as heartbeat, respiratory rate, blood pressure, blood oxygen saturation, and muscle activity. This review comprehensively covers all aspects of recent developments in flexible and stretchable pressure sensors. It encompasses fundamental principles, force/pressure-sensitive materials, fabrication techniques for low-cost and high-performance pressure sensors, investigations of sensing mechanisms (piezoresistivity, capacitance, piezoelectricity), and state-of-the-art applications.

Self-Powered Intelligent Tactile-Sensing System Based on Organic Electrochemical Transistors

“…When V G is 0.9 V, our pressure sensor’s power consumption is 50 μW, which is lower than the values of most reported pressure sensors based on an organic transistor structure. It is worth mentioning that the power consumption and output signal magnitude of most pressure sensors are fixed once they are fabricated, which limit their application scenarios. , In contrast, our OECT-based pressure sensor offers adjustable power consumption and output current by manipulating V G to modify the modulation effect, as illustrated in Figure h. Based on this feature, users can adapt V G based on the detection environment to select an appropriate output current and power consumption.…”

MXene-Based Chemo-Sensors and Other Sensing Devices

“…The Piezoresistive mechanism involves changes in the electrical resistance as a response to mechanical deformation. Flexible pressure sensors using piezoresistive materials, such as certain polymers or carbon-based composites, can detect pressure by measuring variations in resistance [ 69 ]. The Piezocapacitive mechanism is mostly based on monitoring the capacitance changes, which are generated in response to pressure and are the basis of piezocapacitive sensors.…”

“…Most importantly, MXenes typically exhibit high electrical conductivity, which is essential for efficient signal transmission in pressure sensors. This property allows for accurate and rapid detection of pressure changes [ 69 ]. Moreover, MXenes are hydrophilic, meaning they have a strong affinity for water molecules.…”

High-Sensitivity Carbon Nanofibers/Graphene/Polydimethylsiloxane Flexible Pressure Sensor Based on a Hierarchical Structure with Enhanced Sensing Range

“…Flexible pressure sensors have significant potential for application in electronic skin, , health and medical monitoring, − human–computer interaction, − and wearable electronic devices. , Based on the sensing mechanism, these sensors can be classified into four types: capacitive, − piezoelectric, , triboelectric, , and resistive. − Resistive pressure sensors have gained attention due to their simple manufacturing process and easy data acquisition and reading. Sensitivity is a crucial performance parameter of the sensor, as it determines the sensor’s ability to perceive pressure signals.…”