Improved thermoelectric performance of PEDOT:PSS/BiTe/reduced graphene oxide ternary composite films for energy harvesting applications.

We report a significant enhancement in the thermoelectric power of PEDOT by fabricating a novel ternary composite film by incorporating BiTe and rGO. A series of five samples of PEDOT:PSS/BiTe/rGO ternary composite films were synthesized using a spin coating method and having different weight% (0.0, 0.1, 0.2, 0.3 wt%) of rGO in PEDOT:PSS/0.4 wt% BiTe mixture along with pure PEDOT:PSS sample. The Seebeck coefficient, electrical conductivity, and power factor increased in composite films compared to pure PEDOT:PSS films. Incorporating rGO enhanced charge carrier mobility because of its highly conductive network, whereas BiTe provided higher Seebeck coefficients owing to its inherent thermoelectric properties. PEDOT:PSS offered mechanical flexibility and a conductive matrix, facilitating effective phonon scattering and inherently lower thermal conductivity. The sample (PEDOT:PSS/0.4 wt% BiTe/0.1 rGO wt%) demonstrated the highest electrical conductivity of 1522.4 S cm, a Seebeck coefficient of (+) 24.7 μV K, and a power factor of 93.16 μW m K at room temperature. These values represent a twelve-fold increase compared to pristine PEDOT films. A flexible, printable thermoelectric generator (TEG) was also demonstrated on polyimide substrate using inks prepared from p-type PEDOT:PSS/BiTe/rGO and n-type PVDF/Ni NWs. The paper TEG achieved a maximum power output of 242.1 nW, with an output voltage of 9.84 mV and an output current of 49.21 μA at a temperature difference (Δ) of 35 K. XRD, Raman spectroscopy SEM, and XPS techniques were used to understand the underlying mechanism. This novel PEDOT:PSS/BiTe/rGO ternary composite film significantly outperforms previously reported organic thermoelectric materials. The results indicate that the combined effect of PEDOT:PSS, BiTe, and rGO greatly enhances thermoelectric performance, offering a promising and efficient route for the application of PEDOT in advanced thermoelectric conversion processes.