Fully Written Flexible Potentiometric Sensor Using\nTwo-Dimensional Nanomaterial-Based Conductive Ink

Abstract

The\nemerging demand for flexible, portable, easily accessible, and cost-effective\nelectronic fabrication has motivated the development of novel techniques\nto manufacture electronic components and devices. Inspired by daily\nhand-writing, an all-written potentiometric sensor was developed by\nusing a Chinese brush pen-based writing technique. A writing ink made\nfrom graphene nanosheet (GN) as a conductive component, Triton X-100\nas a stabilizer, and xanthan gum as a binder, was used to obtain flexible\nelectrode substrate. Results demonstrate the GN ink-based writing\nelectrode (GN-WE) possesses good conductivity, fast electron-transfer\nkinetics, considerable stability, and favorable flexibility. By further\nwriting cadmium ion selective membrane (Cd²⁺-ISM) and photopolymerized\nreference membrane (RM) on the surface of GN-WE, an all-solid-state\npotentiometric sensor for cadmium ion was constructed. A large bulk\ncapacitance (41.67 μF) and excellent potential stability (drift\nof 0.156 mV h^–1) were achieved at the developed\nall-written potentiometric sensor, which is much superior to the solid-contact\npotentiometric sensor using GCE as electrode substrate. Furthermore,\nreal sample analysis reveals that our GN ink-based potentiometric\nsensor could be used as a reliable and stable sensor for cadmium ion\ndetection in food and in the environment.