Ag Nanowire/CPDMS Dual Conductive Layer Dome-Based Flexible Pressure Sensor with High Sensitivity and a Wide Linear Range

Abstract

Recent research achievements for flexible pressure sensors have promoted promising applications, such as human health detection and intelligent robotics. However, striking a balance between sensitivity and linear detection range is still a challenge. In this paper, a dual conductive layer dome (DCLD) structure, where a silver (Ag) nanowire layer is used as a highly conductive layer and the composite layer of carbon black nanoparticles and polydimethylsiloxane (CPDMS) serves as a low conductive layer, is fabricated with a scratch coating process followed by dip-coating and vacuum adsorption. Benefitting from the dual conductive layer design, the sensitivity of the DCLD sensor reaches 51.7 kPa −1 over an ultrawide pressure of 0.01−250 kPa, which is far better than the CPDMS single conductive layer dome (SCLD). The circuit models of DCLD and SCLD are proposed to disclose their working mechanism. The effects of carbon black nanoparticle ratio in CPDMS and the structural matching between the DCLD structure and electrode on the sensor's performance are explored. The long-cycle stability of DCLD sensors with different fabrication methods is also compared. Additionally, it has been demonstrated that the sensor is efficient in monitoring human motion, such as finger joint flexion, pulse pulses, and human breathing, showing potential in the field of human health monitoring.

Pressure Sensor Based on a Lumpily Pyramidal Vertical Graphene Film with a Broad Sensing Range and High Sensitivity

“…The results show that LPV-5 presents stable responses with excellent repeatability. Figure d shows a high sensitivity response over a wide response range compared to reported pressure sensors, demonstrating the supereminent sensing properties of our LPV-5 sensor. − …”

Transparent and Flexible Graphene Pressure Sensor with Self-Assembled Topological Crystalline Ionic Gel

“…Pressure sensors have attracted considerable interest because of their potential application in different wearable electronics, including soft robotics, artificial electronic skin (e-skin), health monitoring, and mobile displays. − For the practical implementation of pressure sensors, especially in wearable and/or on-body electronics, it is crucial to improve not only their pressure sensitivity and reliability but also their optical transparency and mechanical flexibility. − The majority of pressure sensors are categorized into piezoelectric, piezoresistive, − , and capacitive sensing elements. ,,− Among these, capacitive pressure sensors based on pressure-sensitive capacitance changes of dielectric films are beneficial owing to their rapid response times, low-energy operation, and compact circuit layouts with simple device architectures. Generally, elastomer-based dielectrics have been investigated for achieving efficient large-scale integration combined with a variety of top-down and bottom-up microscale surface-corrugated architectures to further enhance sensor sensitivity.…”

“…Topological surface structures that yield high sensitivities include periodic arrays of micropyramids developed by conventional lithography, , followed by molding with an ionic gel and surface microcones templated with Calathea zebrine leaves . In contrast to previously reported approaches based on the utilization of preformed templates for developing the surface topology of a pressure-sensitive film, ,,, we envisioned that melt recrystallization of a thin semicrystalline polymer/IL blend-type ionic gel, which involves massive crystalline lamellae growth on the air/polymer surface with a large volume contraction, may cost-effectively develop pressure-sensitive self-assembled topological surfaces, resulting in a highly sensitive pressure sensors suitable for large-area flexible sensor arrays.…”

“…1−10 For the practical implementation of pressure sensors, especially in wearable and/or on-body electronics, it is crucial to improve not only their pressure sensitivity and reliability but also their optical transparency and mechanical flexibility. 11−15 The majority of pressure sensors are categorized into piezoelectric, 16 piezoresistive, [6][7][8]17 and capacitive sensing elements. 5,14,18−27 Among these, capacitive pressure sensors based on pressure-sensitive capacitance changes of dielectric films are beneficial owing to their rapid response times, low-energy operation, and compact circuit layouts with simple device architectures.…”

A broad range and piezoresistive flexible pressure sensor based on carbon nanotube network dip-coated porous elastomer sponge

“…Basically, sensitivity, working range and stability of sensors depend on the micro/nanostructures that responded to external stimuli and the electromechanical signal conversion capability of constituent materials. 23,27,28 For example, micro/nanostructures like cracks, 29,30 wrinkles, 31,32 pyramids 33,34 and domes 35,36 could be popularly found in flexible pressure sensors which have a positive impact in realizing ultrahigh sensitivity. And sensing functional materials like MXene, Ag/Au/Cu nanowires, graphene are also frequently employed to develop pressure sensors with high sensitivity, 37–40 which are well known that they are much expensive.…”