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 (NH[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 NH4 is a strong donor in the ammonia gas produced by a bubble system of ammonia water, with NH4 molecules being ideal candidates for molecular doping of graphene. The H2O molecule can facilitate quick desorption by converting NH3 to NH4. The interaction between graphene oxide and NH3 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 NH3 molecules via [Formula: see text] and lone pair electron network. The NH3-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.