The electron impedance spectroscopic study of Poly(3,4-ethylenedioxythiophene)-Poly (sodium 4-styrenesulfonate) modified with organic (RGO) and inorganic (TiO2) compounds

Cross-formalism electrochemical impedance spectroscopy is used to establish quantitative structure–property correlations in chemical-oxidatively synthesized Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) PEDOT-PSS, PEDOT-PSS/TiO₂ (PPT) and PEDOT-PSS/ Reduced Graphene Oxide (PPR) binary nanocomposites screen-printed on cellulose paper. Multi-start nonlinear least-squares fitting of raw impedance data over 4 Hz – 5 MHz identifies a single Rₛ–(R b ∥CPE) circuit for all five compositions (R² > 0.87) with weighted chi-squared values χ² ranging from 2.1 × 10⁻³ to 8.7 × 10⁻³ (all below the 0.01 acceptance threshold) confirming the goodness of fit and yields Jonscher exponents s = 0.80–0.93 (all < 1, confirming hopping conduction across the series). Three quantitative correlations link the XRD-derived structural parameters to the dielectric response. Larger crystallite size T and lower dislocation density δ increase σ dc by one order of magnitude between pristine PEDOT-PSS (T = 0.92 nm) and PPT 20% (T = 15.65 nm); effective capacitance C eff scales with percent crystallinity within the TiO₂ series (127 pF at 58.5%, 18.3 pF at 44.0%); and the CPE exponent n tracks RGO platelet aggregation, dropping from 0.93 at 1.09 nm crystallite size (PPR 20%) to 0.81 at 2.13 nm (PPR 30%). Admittance and electric-modulus spectra confirm a single bulk relaxation (τ Z / τ M = 0.5–6.5) and give a high-frequency permittivity ε ∞ of 5.32 for PPT 20% , consistent with the high electronic polarisability of the anatase (101) lattice imaged by HR-TEM (d = 0.353 nm). The dielectric response of PPT 20% is dominated by Maxwell–Wagner–Sillars polarization at the polymer–anatase interface, while PPR 20% approaches ideal Debye relaxation. The 20 wt% loading is the percolation–aggregation optimum for both filler systems, delivering two device-grade compositions tailored, respectively, for interfacial-polarisation transducers and low-distortion broadband capacitors.