The search for high-performance thermoelectric materials is crucial for advancing energy conversion technologies. In this work, we unveil the remarkable thermoelectric properties of the C3N monolayer, a two-dimensional (2D) material with a tunable band gap of 0.36 eV. Using a combination of the tight-binding model and Green's function approach, we systematically explore the effects of tensile strain, electron doping, and transverse magnetic fields on key transport properties, including the Seebeck coefficient, thermal conductivity, and thermoelectric figure of merit (ZT). Our findings reveal that moderate tensile strain (ϵ = 0.1) significantly enhances ZT, while excessive strain (ϵ = 0.13) deteriorates efficiency due to increased electron scattering. Notably, electron doping optimizes the Seebeck coefficient and enhances thermoelectric performance by increasing carrier concentration. Furthermore, we demonstrate that a transverse magnetic field induces a semiconductor-to-semimetal transition by lowering the band gap, offering a new degree of tunability for electronic and thermoelectric applications. These insights not only establish C3N as a promising candidate for next-generation thermoelectric devices but also open new avenues for engineering 2D materials with optimized energy conversion capabilities.
