Optimizing Conducting MoS₂ Nanosheet Thin Films for Enhanced Electrochemical Interfaces in Biosensing

Developing reliable electrochemical biosensors highly depends on the morphology, uniformity, and stability of the film at the biosensing interface. Molybdenum disulfide nanosheets (MSNs) combined with the conductive polymer Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) have shown great potential for use in electrochemical sensors as this combination can enhance both catalytic activity and electrical conductivity. In this study, three different thin film deposition methods were investigated: (1) bilayer film (BL) of PEDOT:PSS as a base layer and an overlayer of MSNs, (2) mixed material film (Mx) were MSNs and PEDOT:PSS were premixed, and (3) surface-decorated MSNs films (SD) were the particles are introduced to the wet PEDOT:PSS layer prior annealing. This paper investigates the effect of different thin film deposition methods created using spin coating on the structural integrity and stability of the MSNs:PP film. The scanning electron microscopy (SEM) analysis revealed that the MSNs:PP Mx film exhibited the highest uniformity and consistency with minimum aggregation and delamination issues observed in the film. Furthermore, electrochemical characterization using cyclic voltammetry (CV), showed increased peak current response to 13 µA compared with bare MSNs films. The electrochemical impedance spectroscopy (EIS) demonstrated improved charge transfer properties with 97.88% reduction in Rct compared to MSNs. These findings establish MSNs:PP thin films as promising candidates for fabricating a stable and sensitive biosensing interfaces with a potential application in biomedical diagnostics.