Effect of Dielectric Barrier Discharge (DBD) Plasma on Structural and Electrical Properties of Polypyrrole (PPy) Thin Films

Cold plasma treatment is an effective approach for surface modification of conducting polymers, enabling the tuning of their structural and electronic properties without altering the bulk composition. In this work, polypyrrole (PPy) thin films were fabricated on indium tin oxide (ITO) substrates via electrochemical deposition. The films were subsequently exposed to dielectric barrier discharge (DBD) cold plasma for different exposure times (0, 5, 10, 15, and 20 min). The structural modifications induced by plasma treatment were investigated using X-ray diffraction (XRD), while the electrical and charge transport properties were analyzed using Hall effect measurements. The XRD results revealed significant changes in peak intensity and crystallinity, indicating surface activation and partial reorganization of polymer chains upon plasma exposure. Hall effect measurements showed systematic variations in carrier concentration, mobility, and electrical conductivity as a function of plasma treatment time, confirming the strong influence of surface modification on charge transport behavior in PPy films. The results demonstrate that DBD cold plasma treatment provides a controllable and effective route for enhancing the structural ordering and electrical performance of electrochemically deposited PPy thin films, making them promising for applications in sensors, optoelectronic devices, and flexible electronics.