A highly sensitive pressure sensor using a double-layered graphene structure for tactile sensing

Abstract

In this paper, we propose a graphene sensor using two separated single-layered graphenes on a flexible substrate for use as a pressure sensor, such as for soft electronics. The working pressure corresponds to the range in which human perception recognizes surface morphologies. A specific design of the sensor structure drives the piezoresistive character due to the contact resistance between two graphene layers and the electromechanical properties of graphene itself. Accordingly, sensitivity in resistance change is given by two modes for low pressure (-0.24 kPa(-1)) and high pressure (0.039 kPa(-1)) with a crossover pressure (700 Pa). This sensor can detect infinitesimal pressure as low as 0.3 Pa with uniformly applied vertical force. With the attachment of the artificial fingerprint structure (AFPS) on the sensor, the detection ability for both the locally generated shear force and actual human touch confirms recognition of the surface morphology constructed by periodic structures.

Highly Sensitive, Flexible MEMS Based Pressure Sensor with Photoresist Insulation Layer

“…Sensitivity is the most important technical parameter of pressure sensors. The sensitivity of most piezoresistive pressure sensors can be calculated by the following equation:where Δ P is the change of applied pressure, Δ I is the change of current corresponding to pressure, I off is the initial current. However, our sensor is a zero‐power‐consumption device in off state that I off is zero.…”

Wearable Mechanotransduced Tactile Sensor for Haptic Perception

“…For example, Park et al developed an ultrasensitive interlocking microstructured ferroelectric film capable of discriminating surface texture down to 100 µm with low scanning speed of 2.5 mm s −1 . Similarly, Chun et al designed a flexible double‐layered graphene structure that senses periodic structures of 100 µm pitch . They further developed a similar graphene–sponge composite using polyethylene terephthalate (PET) ridges to enhance surface texture recognition .…”

Graphite nanobelts characterization and application for blood pulse sensing

“…The need for flexible, skin-friendly wearable electronics has attracted much interest in the last decade, with numerous possible applications that span from simple recreational exercise monitoring to rare heart disease diagnostics and soft robotics [1][2][3]. Integration of sensing materials with flexible substrates and elements for signal detection and processing is highly required and involves multidisciplinary researches [1][2][3][4][5][6][7][8].…”

“…One of the most suitable materials for wearable electronics is graphene in different forms (from a single to multiple layers) which has excellent mechanical properties and high electrical conductivity [5,8,9]. Among different forms of graphene based materials, nanographite structures that can have lateral size up to tens of microns and thickness from a few to tens of nanometers currently attracts increasing attention [9].…”

“…Low fabrication costs, easy procedures for manipulation and transfer onto different types of substrates make this material promising for flexible electronics [10,11]. Graphene or nanographite-based devices, using fibers [2], layered [8] or network [12,13] graphitic materials showed high sensitivity and reproducibility for strain, pressure and blood pulse sensing.…”