Chemi-Resistive Sensor for Ammonia Using Inkjet Printing of GO/PEDOT:PSS Composite at Room Temperature

Abstract

This study describes an easy and cheap inkjet printing method for producing a paper-based gas sensor consisting of a composite film made of graphene oxide and poly(3,4-ethylenedioxythiophene) and poly(styrenesulfonate) (PEDOT:PSS). A glossy paper substrate is an inkjet printed with ink made by dispersing graphene oxide in a PEDOT:PSS conducting polymer solution to test its ability to detect ammonia ([Formula: see text] at ambient temperature. The presence of few-layer graphene oxide in the PEDOT:PSS copolymer and the existence of [Formula: see text]–[Formula: see text] interactions between graphene oxide and PEDOT:PSS are confirmed by Fourier transform infrared spectroscopy, UV–Visible spectrophotometer, and X-ray diffraction. In a small concentration range of 1–100 ppm at ambient temperature, the ink-jet printed graphene oxide-PEDOT:PSS gas sensor displays strong responsiveness and good selectivity to NH3. The study found that [Formula: see text] is a strong donor in the ammonia gas produced by a bubble system of ammonia water, with [Formula: see text] molecules being ideal candidates for molecular doping of graphene. The [Formula: see text] molecule can facilitate quick desorption by converting [Formula: see text] to [Formula: see text]. The interaction between graphene oxide and [Formula: see text] molecules is weak. The attained gas-sensing performance may be attributed to the increased specific surface area of graphene oxide and enhanced interactions between the sensing film and [Formula: see text] molecules via [Formula: see text] and lone pair electron network. The [Formula: see text]-sensing mechanisms of the flexible printed gas sensor are based on the competitive interaction of ammonia on the sensor, adsorption and dissociate ionization on the sensor surface.