The thermoelectric power investigation of the Γ2-graphyne molecule device

Graphyne, is an interesting carbon nanostructure, with unique properties such as high carrier mobility, thermal stability, and electronic band characteristics shaped by sp and sp(2) hybridizations. Due to its intrinsic porous nature, graphyne exhibits higher phonon scattering, and lower thermal conductance compared to graphene, making it an excellent nominee to be investigated as an organic nanoscale thermoelectric material. In this study, we delve into the thermoelectric power properties of the Gamma 2-Graphyne structures using the modeling and simulated approaches. Our modeling studies focus on unit cell base vector variation at temperatures higher and lower than the Fermi temperature, additionally, the hopping energy variation is calculated in the same temperatures. Wehave employed the semi-classical Boltzmann transport equation to analyze these effects, considering the relaxation time factor, as a way of exploring the phonon scatterings, and the changing system behavior. It is concluded structural variation leads to a change in the scattering mechanisms. ATK Quantum Wise simulations on three groups of Gamma 2-Graphyne structures are carried out. In the first two groups, the influence of the electrode length and the asymmetry are investigated, but for the last group, only the main region variation is considered. Generally, the number of the unit cells in the main region is changed from one group to the other. The density of states, the transmission spectrum, and electrical conductance values are calculated moreover, the effect of the temperature on thermoelectric power for all groups of devices is simulated. The figure of merit (Z) values at room temperature for all the structures is determined and the highest value of ZT is for the device with one unit cell and asymmetric electrodes are reported.