## 3 Results and Discussion
### Thermoelectric Properties  
In this section, the thermoelectric properties of monolayer and multilayer Mo\({}_{2}\)C- are investigated because their structure has been shown to have good mobility [23]. In general, at high temperatures and low chemical potential, charge carriers reduce the Seebeck coefficient and the electrical conductivity and increase the thermal conductivity of the Mo\({}_{2}\)CF\({}_{2}\) and Mo\({}_{2}\)C(OH)\({}_{2}\) semiconductors. The Seebeck coefficient \(S\), calculated at different temperatures as a function of the chemical potential, is shown in Figure 5. The results show that at room temperature, monolayer Mo\({}_{2}\)C(OH)\({}_{2}\) and Mo\({}_{2}\)CF\({}_{2}\) attained high Seebeck coefficients of about 285 \(\upmu\)V K\({}^{-1}\) and 400 \(\upmu\)V K\({}^{-1}\), respectively. This indicates that, with the large transition of the DOS, large Seebeck coefficient values can be obtained. Particularly, an interesting transition from p-type to n-type is shown for the Mo\({}_{2}\)CF\({}_{2}\) and Mo\({}_{2}\)C(OH)\({}_{2}\) semiconductors, representing the chemical potential transition from a low carrier concentration to a high concentration. The calculation results for the Seebeck coefficient of Mo\({}_{2}\)CO\({}_{2}\) showed a drastic transition, especially at room temperature. Bilayer Mo\({}_{2}\)CF\({}_{2}\) with a band gap of 0.258 eV still exhibited a large Seebeck coefficient (\(\sim\)395 \(\upmu\)VK\({}^{-1}\)) and a relatively high conductivity (\(\sim\)9 \(\times\) 10\({}^{19}\)\(\Omega\)\({}^{-1}\) cm\({}^{-1}\) s\({}^{-1}\)) at low carrier concentrations, and, therefore, a high power factor. Mo\({}_{2}\)C(OH)\({}_{2}\) had a smaller band gap (0.012 eV) with a smaller Seebeck coefficient compared to Mo\({}_{2}\)CF\({}_{2}\) (\(\sim\)150 \(\upmu\)VK\({}^{-1}\)), as well as a small electrical conductivity near its band edges. Meanwhile, Mo\({}_{2}\)CO\({}_{2}\) was still metallic and did not exhibit better TE properties. The calculations demonstrate that Mo\({}_{2}\)CF\({}_{2}\) and Mo\({}_{2}\)C(OH)\({}_{2}\) can be promising TE materials in the low- and intermediate-temperature  
Figure 5: Seebeck coefficient as a function of the chemical potential for monolayer and multilayer at different temperatures for Mo\({}_{2}\)CF\({}_{2}\), Mo\({}_{2}\)C(OH)\({}_{2}\), and Mo\({}_{2}\)CO\({}_{2}\). regions. This is consistent with theoretical predictions [23], which found that Mo\({}_{2}\)CF\({}_{2}\) nanosheets achieved larger power factors compared to other functionalized MXenes. Figure 6 shows the electrical conductivity of Mo\({}_{2}\)C-structures as a function of chemical potential at different temperatures. From \(-0.4\) to \(-0.1\) eV, the electrical conductivity decreased as the temperature increased from 300 K to 600 K. The monolayer Mo\({}_{2}\)CF\({}_{2}\) obtained the maximum electrical conductivity value at around \(-0.3\) eV. Moving towards higher chemical potential values, the observed temperature-dependent electrical conductivity was reversible at around \(-0.15\) eV for Mo\({}_{2}\)CF\({}_{2}\) and Mo\({}_{2}\)C(OH)\({}_{2}\) and \(-0.1\) eV for the monolayer Mo\({}_{2}\)CO\({}_{2}\), in which the electrical conductivity increased as the temperature increased. The calculation results of electronic thermal conductivity as a function of chemical potential at different temperatures are presented in Figure 7. For the electronic thermal conductivity, a similar trend was observed for all three Mo\({}_{2}\)C-MXenes. At small chemical potential values or at high temperature values, the electronic thermal conductivity was higher, tended to be steeper, and gradually decreased to a minimum value at an energy level equal to the Fermi level. Unlike the rapid change detailed above, the dependence of thermal conductivity on temperature at large chemical potential values underwent a slow change.