Polyaniline/graphitic carbon nitride/reduced graphene oxide ternary nanocomposite film for flexible thermoelectric application

The present study outlines the preparation of a ternary nanocomposite film comprising of polyaniline doped with camphor sulfonic acid (PANI), reduced graphene oxide (rGO), and graphitic carbon nitride (g-C₃N₄), and delves into its thermoelectric performance. PANI is known to possess high electrical conductivity (<i>σ</i>) and poor thermal conductivity (<i>κ</i>). However, its potential for thermoelectric applications is constrained by the low value of the Seebeck coefficient (<i>S</i>). The incorporation of g-C₃N₄in PANI has been demonstrated to result in an improvement of the Seebeck coefficient. Furthermore, the addition of rGO to the PANI/g-C₃N₄sample counteracts the decrease in electrical conductivity. The PANI/g-C₃N₄/rGO ternary nanocomposite film exhibits an enhanced Seebeck coefficient of ∼2.2 times when compared to the PANI sample. The Seebeck coefficient of the PANI/g-C₃N₄/rGO nanocomposite is enhanced by the energy filtering effect that occurs at the interfaces between g-C₃N₄/PANI and PANI/rGO. The<i>π</i>-<i>π</i>interaction between the PANI chains and rGO is responsible for the increased electrical conductivity resulting from the well-ordered polymer chain arrangement on the g-C₃N₄and rGO surfaces. The ternary nanocomposite sample demonstrated a synergistic improvement in both electrical conductivity and Seebeck coefficient, resulting in a remarkable ∼4.6-fold increment in power factor and an ∼4.3-fold enhancement in the figure of merit (<i>zT</i>), as compared to the pristine PANI film.