Tight-binding and NEGF analysis of high-performance thermoelectric transport in MXene nanoribbons

The electronic thermoelectric properties of one-dimensional MXene nanoribbon devices were explored by adopting a tight-binding Hamiltonian coupled with the non-equilibrium Green’s function (NEGF) formalism. The model device configuration involves finite Ti 3 C 2 O 2 , Sc 3 C 2 F 2 , and Zr 3 C 2 O 2 nanoribbon channels connected to graphene electrodes. Calculations of the temperature-dependent electronic thermoelectric coefficient were performed in order to obtain the figure of merit ( ZT ₑ) for the electronic contribution, Seebeck coefficient, power factor, and normalized conductance ( G / G 0 ). The results revealed that the best p-type performance of Ti 3 C 2 O 2 is attained at μ = 0.89 eV, yielding very high ZT ₑ values of 4.9 at 300 K and up to 5.5 at 500 K. On the other hand, Zr 3 C 2 O 2 shows the strongest n-type response, with a ZT ₑ of approximately 4.7 at 300 K and with the highest conductance compared to all other studied systems. Sc 3 C 2 F 2 also presents a promising n-type performance with a maximum ZT ₑ of approximately 3.3 at 300 K. In all the studied structures, the power factors remained moderate due to the limited number of conducting channels available in finite one-dimensional nanoribbons. These results lead to an overall, consistent assessment of the electronic thermoelectric properties across different MXene nanoribbon compositions.