Iontronic pressure sensor with ultra-board linear range and high sensitivity enabled by laser-induced gradient pyramidal structures

Abstract

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 at low cost. This work presents a facile and low-cost fabrication method to integrate an ultrathin ionic layer with gradient microstructures with programmable profiles and heights created by a simple CO2 laser. The coupled electrical and mechanical simulations provide a route to optimize the design of iontronic pressure sensors based on the electric double layer to address the existing challenges for significantly improved pressure sensing performance. The resulting optimized sensor exhibits a high sensitivity of 33 kPa− 1 over an ultra-board linear sensing range of 1700 kPa, an ultralow detection limit of 0.36 Pa, and a pressure resolution of 0.00725% under ultrahigh pressure of 2000 kPa. Taken together with a rapid response/recovery time of 4/16 ms and excellent repeatability over 4,500 cycles, the sensor has been applied to subtle pulse detection from the fingertip, interactive control on the robotic hand, and a smart weight scale/chair with ultrahigh pressure resolution. The simple 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 the opportunities to create other iontronic sensors for the next-generation flexible devices.