Ultra-Sensitive Flexible Pressure Sensor Based on Microstructured Electrode

Abstract

Flexible pressure sensors with a high sensitivity in the lower zone of a subtle-pressure regime has shown great potential in the fields of electronic skin, human–computer interaction, wearable devices, intelligent prosthesis, and medical health. Adding microstructures on the dielectric layer on a capacitive pressure sensor has become a common and effective approach to enhance the performance of flexible pressure sensors. Here, we propose a method to further dramatically increase the sensitivity by adding elastic pyramidal microstructures on one side of the electrode and using a thin layer of a dielectric in a capacitive sensor. The sensitivity of the proposed device has been improved from 3.1 to 70.6 kPa−1 compared to capacitive sensors having pyramidal microstructures in the same dimension on the dielectric layer. Moreover, a detection limit of 1 Pa was achieved. The finite element analysis performed based on electromechanical sequential coupling simulation for hyperelastic materials indicates that the microstructures on electrode are critical to achieve high sensitivity. The influence of the duty ratio of the micro-pyramids on the sensitivity of the sensor is analyzed by both simulation and experiment. The durability and robustness of the device was also demonstrated by pressure testing for 2000 cycles.

Recent Progress on Flexible Capacitive Pressure Sensors: From Design and Materials to Applications

“…designed a micro‐structured dielectric based flexible capacitive pressure sensor in which one electrode is deposited on the microstructure while the other electrode is a layer of Parylene/ITO/PET. [ 107 ] PDMS is spin‐coated on a mold of KOH‐etched <100> silicon pyramidal microgrooves. After peeling‐off the PDMS, which then has micro‐pillars, Ti/Au is deposited on the micro‐pyramids.…”

Flexible and Stretchable Capacitive Sensors with Different Microstructures

“…[32] In addition, capacitive sensors have the advantages of simple device structure, low power consumption, low detection limit, wide application range, fast dynamic response, and endurability, [35][36][37][38][39][40][41] which have been extensively studied and applied in E-skin, [42,43] medical prosthetics, [44] wearable devices, [13,45] biometrics, [38,46] touchpads and touch screens, [47][48][49] and other consumer electronics fields. [47,[50][51][52][53] In the past few decades, various methods for fabricating flexible capacitive sensors have been proposed. The early preparation methods of capacitive sensors are mostly based on microelectromechanical system (MEMS) technology.…”

Transduction Mechanisms, Micro-Structuring Techniques, and Applications of Electronic Skin Pressure Sensors: A Review of Recent Advances

“…of Au on PI. Sandpaper as mold 3302.9 (0–10) 671.7 (10–100) 229.9 (100–360) 0.08 Pa/ 360 kPa 9/18 5000 (L) 2000 (B) -/- (♡) C M. Zhang [ 278 ] 2020 Parylene with elec. of Au-coated PDMS micro-pyramids (35 µm of width, 24.7 µm of height) and ITO on PET.…”