An ultrahigh sensitivity micro-cliff graphene wearable pressure sensor made by instant flash light exposure

Nanoscale. 2021 Sep 23;13(36):15380-15393. doi: 10.1039/d1nr04333a.

Abstract

Wearable and highly sensitive pressure sensors are of great importance for robotics, health monitoring and biomedical applications. For simultaneously achieving high sensitivity within a broad working range, fast response time (within a few milliseconds), minimal hysteresis and excellent cycling stability are critical for high performance pressure sensors. However, it remains a major challenge. Herein, we report a conceptual micro-cliff design of a graphene sensor with a record high sensitivity of up to 72 568 kPa-1 in a broad working range of 0-255 kPa, which is one order of magnitude higher than the state-of-the-art reported sensitivity. In addition, the detection limit can be as low as 0.35 Pa and the fast response time is less than 5 ms. The sensor also has a minimal hysteresis and an outstanding cycling stability of 5000 cycles, all of which meet the requirements of an ideal pressure sensor. More interestingly, the micro-cliff graphene sensor is made by the fast and scalable flash reduction of graphene oxide using a single flashlight pulse within 150 ms and has been integrated into a wearable smart insole and an E-glove prototype for demonstration of health monitoring applications. This micro-cliff graphene pressure sensor achieves record-high sensitivity, which brings new possibilities in sensor research and promises broad applications.