Iontronic pressure sensor with high sensitivity over ultra-broad linear range enabled by laser-induced gradient micro-pyramids

Abstract

Despite the extensive developments of flexible capacitive pressure sensors, it is still elusive to simultaneously achieve excellent linearity over a broad pressure range, high sensitivity, and ultrahigh pressure resolution under large pressure preloads. Here, we present a programmable fabrication method for microstructures to integrate an ultrathin ionic layer. The resulting optimized sensor exhibits a sensitivity of 33.7 kPa−1 over a linear range of 1700 kPa, a detection limit of 0.36 Pa, and a pressure resolution of 0.00725% under the pressure of 2000 kPa. Taken together with rapid response/recovery and excellent repeatability, the sensor is applied to subtle pulse detection, interactive robotic hand, and ultrahigh-resolution smart weight scale/chair. The proposed fabrication approaches and design toolkit from this work can also be leveraged to easily tune the pressure sensor performance for varying target applications and open up opportunities to create other iontronic sensors.

Normal-Direction Graded Hemispheres for Ionic Flexible Sensors with a Record-High Linearity in a Wide Working Range

“…As the most representative work in terms of sensitivity and sensing range, Yang et al exhibit a sensor with a sensitivity of 33.7 kPa −1 over a linear range of 1700 kPa. 41 As sensors with graded microstructures, Bai et al achieved a sensitivity of up to 3302.9 within the range of 0−360 kPa, but the linearity was poor in that region, and the sensing curve was divided into three segments. In their subsequent research, they achieved a balance between sensitivity, linearity, and sensing range (S ∼ 49.4 kPa −1 and R 2 = 0.999 in the range of 0−485 kPa).…”

Flexible Capacitive Pressure Sensor with High Sensitivity and Wide Range Based on a Cheetah Leg Structure via 3D Printing

“…With the use of these flexible materials, researchers can achieve more innovative structural patterns. Yang et al 34 used a laser with a Gaussian beam to prepare an ion-based device with an optimized sensitivity of 33.7 kPa −1 . Chen et al 35 fabricated asymmetric structures based on poly(vinylidene fluoride) by an electrostatic spinning process, and this type of sensor reached a sensitivity of 55 kPa −1 and a sensing range of 66.67 kPa.…”

“…Chen et al fabricated asymmetric structures based on poly­(vinylidene fluoride) by an electrostatic spinning process, and this type of sensor reached a sensitivity of 55 kPa –1 and a sensing range of 66.67 kPa. Most capacitive pressure sensors use laser technology, − electrostatic spinning, and other transfer methods to construct microstructures. Although these results provide an impressive performance, the preparation process is time-consuming, complex, and costly.…”

Stretchable, Adhesive, and Bioinspired Visual Electronic Skin with Strain/Temperature/Pressure Multimodal Non-Interference Sensing

“…Human skin, containing lots of receptors for sensing and distinguishing multiple stimuli, is one of the most important somatosensory systems. , Artificial multifunctional electronic skin (e-skin) that can mimic and even surpass the human skin sensory functions is anticipated to play an important role in personal healthcare, − prosthetics, − soft robotics, − human–machine interaction, − and other fields. − However, cross-talks prevent accurate measurements of the target input signals when parts of them are simultaneously present . In general, several combination effects of the materials (e.g., thermoelectric, piezoresistive, triboelectric, capacitive, and ferroelectric) and structural engineering (e.g., hierarchical patterns, nanohelixes, micropyramids, microridges, and interlocked microstructures) yielding different signals are the most straightforward method to design multimodal sensors with decoupled sensing mechanisms.…”