Ammonia‐Sensing Using a Composite of Graphene Oxide and Conducting Polymer

The paper studies the performance of a gas sensor based on an organic/inorganic diode for ammonia (NH 3 ) sensing under atmospheric conditions at room temperature and different humidity levels. The diode structure consists of a layer of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) deposited on top of n‐type GaAs. The PEDOT:PSS layer that is filled with different ratios of graphene oxide (GO) is prepared from the solution phase. We show that the current–voltage ( I–V ) response of the diode and the sensing performance improve significantly by adding GO to the PEDOT:PSS layer. The sensing response is highest for a diode with 0.04 wt.% of GO. At room temperature, the PEDOT:PSS:GO (0.04 wt.%)/n‐GaAs Schottky diode shows a sensitivity of 194 upon exposure to 20 ppm of NH 3 with rapid response and recovery times between 95 and 121 s, respectively. The NH 3 sensor based on PEDOT:PSS:GO is cost‐effective, environmentally friendly, and easy to fabricate using low‐cost solution‐processing methods.