Highly Sensitive Ammonia Gas Sensors Based on Unidirectional Graphene Oxide Polymer Nanocomposite Thin Films

Authors:
Publisher website
Google Scholar
Abstract
In this work, we demonstrate a highly sensitive ammonia (NH3) gas sensor based on organic field-effect transistors (OFETs) with a polymer nanocomposite of graphene oxide (GO) and the conjugated polymer Poly[N-9’-heptadecanyl-2,7-carbazole-alt-5,5-(4’,7’-di-2-thienyl-2’,1’,3’-benzothiadiazole)] (PCDTBT) as the active semiconductor channel. The nanocomposite semiconductor was fabricated using the unidirectional floating film transfer method (UFTM) at the liquid-air interface, enabling the preparation of highly oriented thin films with good molecular ordering. Our approach leverages UFTM-induced molecular orientation in a GO–conjugated polymer nanocomposite to simultaneously achieve ultrafast response, high sensitivity at low NH3 concentrations, and exceptional operational robustness under harsh conditions. The resulting OFET sensors exhibit an outstanding sensing response of approximately 80% at a ammonia concentration of 20 ppm, with response and recovery times of 3 and 5 s, respectively, under ambient conditions (~30 °C). Moreover, the devices showed superior stability under harsh environmental conditions, maintaining their sensing performance at temperatures up to 100 oC and relative humidity of 85%. The sensors also maintained their performance over an extended period of 90 days. The enhanced orientation and molecular packing of the polymer films achieved by UFTM are responsible for the high sensitivity, reliability, and stability of the fabricated OFET-based ammonia sensors.
Funding Information
  • LOTUS Program under JST for a Visiting Fellowship

This publication has 48 references indexed in Scilit: