Selective Hg2+ sensor: rGO-blended PEDOT:PSS conducting polymer OFET

Abstract

The detection of water pollutants employing organic field-effect transistor (OFET) sensor requires a stable performance in an aqueous media. It is an essential condition of any sensor to present reliable measurements. Some organic-conducting polymers deteriorate almost immediately in the presence of an aqueous medium. However, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has proven its stability in both air and aqueous mediums. Nevertheless, due to inadequate structural and chemical properties of the PEDOT:PSS, it persists major obstacles and inhibits its performance in practical applications. These shortcomings can be overcome with the combination of carbon nanomaterials. Therefore, the present study deals with the effect of inclusion of reduced graphene oxide (rGO) into PEDOT:PSS, and it resulted in the enhancement of structural, morphological, and electrical properties of the PEDOT:PSS/rGO nanocomposite. The organic field-effect transistor (OFET) was fabricated with PEDOT:PSS/rGO nanocomposite to detect heavy-metal ions. This makes a highly sensitive and selective sensor platform for detecting Hg2+ in the linear concentration range of 1–60 nM. The presented OFET sensor manifests high sensitivity and selectivity to Hg2+ with a low detection limit of 2.4 nM. The variety of metal ions tested, i.e., Hg2+, Cd2+, Pb2+, Cu2+, Zn2+, Na+, and Fe3+, to investigate the selectivity. The sensor exhibits stable performance in an aqueous medium for the detection of Hg2+ in the presence of DI water. Moreover, the OFET sensor responded within 2–3 s after incubation of Hg2+ ions’ solution.