Solid-State rGO-PEDOT:PSS Transducing Material for Cost-Effective Enzymatic Sensing

Abstract

Performance of a sensing device is dependent on its construction material, especially for components that are directly involved in transporting and translating signals across the device. Understanding the morphology and characteristics of the material components is therefore crucial in the development of any sensing device. This work examines the morphological and electrochemical characteristics of reduced graphene oxide interspersed with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (rGO-PEDOT:PSS) used as a transducer material deposited on a commercially available screen-printed carbon electrode (SPCE). Electron microscopy shows that PEDOT:PSS is interspersed between rGO layers. Raman and XRD analyses suggest that the graphene crystallinity in GO-PEDOT:PSS and rGO-PEDOT:PSS remains intact. Instead, PEDOT:PSS undergoes a change in structure to allow PEDOT to blend into the graphene structure and partake in the π-π interaction with the surface of the rGO layers. Incorporation of PEDOT:PSS also appears to improve the electrochemical behavior of the composite, leading to a higher peak current of 1.184 mA, as measured by cyclic voltammetry, compared to 0.522 mA when rGO is used alone. The rGO-PEDOT:PSS transducing material blended with glucose oxidase was tested for glucose detection. The sensitivity of glucose detection was shown to be 57.3 µA/(mM·cm2) with a detection limit of 86.8 µM.

Synthesis of nickel hydroxide/reduced graphene oxide composite thin films for water splitting application

“…37 The band at 1015 cm −1 is assigned to carbonyl group from rGO nanosheet. 38 From the Raman spectra, it is seen that a Ni(OH) 2 nanosheet exhibits a peak at 3650 cm −1 corresponding to the symmetric stretching of the hydroxyl group (νO H). Also, a peak at 310 and 473 cm −1 is assigned to Eg and A1g lattice mode of Ni OH, respectively.…”

A Graphene-PEDOT:PSS Modified Paper-Based Aptasensor for Electrochemical Impedance Spectroscopy Detection of Tumor Marker

“…In the representation of the Nyquist plot, the diameter of the semicircle gives the magnitude of the charge transfer resistance (Rct) at the electrode surface [28]. From the upper left corner of Figure 3b, it can be seen that the Rct (19.64 Ω) of the graphene/PEDOT:PSS modified paper electrode impregnated with methanol (red circle) is smaller than that (36.04 Ω) of the unmodified methanol (black square) one, which confirms that alcohols can improve the electrical conductivity of PEDOT:PSS [23]. When the amino functional group of APTES (blue triangle) is modified on the surface of the paper electrode, it can block the function of partial electron transfer and increase the Rct (358.4 Ω).…”

“…Figure 2f shows that the surface of the methanol treated graphene/PEDOT:PSS modified paper electrode is more homogenous than that of the untreated one. This improvement in the morphology enhances the electrical conductivity of the paper electrode [23].…”

“…After coating the graphene ink, the filter paper was immersed in PEDOT:PSS solution for 1 hour, followed by spinning the filter paper at 4000 rpm for 3 min so that the PEDOT:PSS could be evenly distributed on the paper and annealed on a hotplate at 100 °C for 5 min. In order to enhance the conductivity of the graphene/PEDOT:PSS modified paper electrode, the paper was further treated with methanol at 100 °C for 5 min [23], then, dried in the air.…”

“…It is observed that voids of fibers are roughly filled with graphene. With further absorption of PEDOT:PSS, the remaining interspace between the graphene and fibers as well as the interlayer spacing of graphene seem to be filled with PEDOT:PSS [23]. Figure 2d,e show the SEM images at 10,000× magnification of the paper electrode in three fabrication steps.…”