Maximizing Thermoelectric Performance of Monolayer C3N Through Strategic Adsorption with Emerging Dumbbell Geometry

Following the controllable large-scale synthesis of Two-dimensional (2D) Polyaniline or ${\mathrm{C}}_3\mathrm{N}$ (Nature 638 2025, Adv. Mat. 29 2017), a significant amount of effort is devoted to enriching its unique characteristics. In this article, the exotic transport features of the ${\mathrm{C}}_3\mathrm{N}$-based family of unique dumbbell-like morphologies (J. Phys. Chem. C202312718001) of indirect semiconducting electronic nature, are explored leading to distinctive thermoelectric (TE) responses. A fundamental understanding from the structural and electronic points of view initially sets the tone of the analysis. The ‘light-heavy’ admixture of primary band valleys added to the heavier secondary valley convergence entertains highly anisotropic carrier mobilities with large Seebeck coefficients. Higher weighted mobility added to substantial anharmonic scattering reduces the lattice thermal conductivity, imparting a decent thermoelectric quality factor. The applicability of acoustic deformation potential theory is thoroughly discussed and validated as sufficiently capable of yielding reasonable carrier relaxation times. Large room temperature power factors at optimum carrier concentrations lead to a maximum thermoelectric figure of merit of 0.81 at 300 K and nearly 1 at 900 K. All these findings critically address the waste heat management abilities of these upcoming synthesized dumbbell geometries (J. Phys. Chem. C 2021 125 17906), providing a pathway for designing futuristic efficient, metal-free, earth-abundant elemental thermoelectric devices.