Multi-sized planar capacitive pressure sensor with ultra-high sensitivity

Abstract

It is now widely accepted that the capacitive pressure sensor has potential benefits for future robotic technologies, human-machine interface, artificial intelligence and health monitoring devices. Despite this fact, the conventional stacked structure including an intermediate dielectric layer between the neighboring electrode layers usually possesses considerable device thickness and size, thus imposing limits on the applicable scale. Here we develop a planar structured pressure sensor without the integrated elastic dielectric layer, and ultra-high sensitivity is achieved enabled by the emerging charge exchange channels between neighboring electrodes induced by external touching stimuli. Each pixel can be fabricated within a several-micrometer range and a tiny pressure of 0.02 Pa would result in a 750% increase in the relative capacitance (equivalent sensitivity of 3.75 × 10 5 kPa −1 for 0–0.05 Pa, exceeding all the previous reports to date). The working mechanisms are quantitatively investigated and proved to be applicable to macro-sized devices. Simultaneously, we illustrate the capabilities of such sensors by using them to perform static pressure mapping, generating capacitance signals to reflect its own surface morphology when the AFM tip passes by, detecting fingers touching, recording real-time human breath, and distinguishing the contact position. This work develops a planar structured pressure sensor without the integrated elastic dielectric layer, and ultra-high sensitivity (3.75 × 10 5 kPa −1 for 0–0.05 Pa) is achieved enabled by the emerging charge exchange channels between neighboring electrodes induced by external touching stimuli. Such devices can sense external stimuli based on the emerging charge exchange channels and be fabricated within wide scale ranges (from several micrometers to several millimeters). The practical application, like revealing the sample surface morphology in atomic force microscope (AFM), detecting fingers touching, recording real-time human breath, and distinguishing the contact position is also demonstrated in this research. • A planar capacitive pressure sensor is developed based on the emerging charge exchange channels between electrodes. • Multi-sized devices were fabricated from several micrometers to several millimeters without the limits of elastomer layers. • Micro-sized pressure sensor can reach an equivalent sensitivity of 3.75 × 10 5 kPa −1 for 0–0.05 Pa.