theoretical investigation of 2d mxenes for thermoelectric application

Abstract

The increasing demand for sustainable, eco-friendly, affordable, and renew- newlineable energy resources has become a primary focus for researchers to over- newlinecome the energy requirements of society. A significant portion of the energy newlineis dissipated as thermal energy in industrial and household operations, and newlinethermoelectric materials can convert the waste heat into electricity. The newlineperformance of thermoelectric materials, determined by the figure of merit newline(ZT), depends on their electrical and thermal transport properties. A new newlineclass of 2D materials known as MXenes with the general formula M n+1 X n T x newline[where M represents early transition metals such as Sc, Zr, Hf, Mo, Ta, Ti, newlineHf, V, Nb; X is C and/or N and T x are surface terminating groups such newlineas O, OH, F, S, Se, Te] has attracted significant attention for the renew- newlineable energy applications due to their high electrical conductivity, excellent newlinestructural and chemical stabilities. This thesis investigates the thermo- newlineelectric performance of 2D MXenes by considering electron and phonon newlinetransport, combining density functional theory (DFT) with a semi-classical newlinemodel based on the Boltzmann transport equation (BTE). newlineWe have first investigated the thermoelectric performance of Janus mono- newlinelayer MoWCO 2 , observing a significant impact of surface scattering on newlinephonon transport. Surface scattering reduced the lattice thermal conduc- newlinetivity (and#954; l ) by approximately 80% for a ribbon width (L) of 1µm, while the newlineelectrical conductivity remains unchanged at room temperature. This re- newlineduction in thermal conductivity leads to the enhancement of ZT to 0.33 for newlinep-type and 0.08 for n-type at 700 K for L=10 nm, compared to 0.04 for newlinep-type and 0.01 for n-type. Furthermore, the mechanical and piezoelectric newlinecoefficients of MoWCO 2 were determined, finding Young s modulus of 244 newlineN/m and Poisson s ratio of 0.55, indicating the material s ability to deform newlineunder small strain. The in-plane piezoelectric coefficients, e 11 = 268 pC/m newlineand d 11 = 1.6 pm/V, suggest that MoWCO 2 is suitable for wea