Supplementary material from "Three distinct conductance states in polycyclic aromatic hydrocarbon derivatives"

Tight binding model and density functional theory calculations were employed. Both simulations have demonstrated that the electrical conductance for eight polycyclic aromatic hydrocarbons can be modulated by varying the number of aromatic rings within the aromatic derivatives. TBM simulations reveal three distinct conductance states: low, medium and high for the studied PAHs derivatives. The three distinguished conductance states suggest by TBM are supported by DFT transmission curves, where the low conductance evidenced by T(E)= zero, for Benzene, Naphthalene, Pyrene and Anthracene. While Azulene and Anthanthrene exhibit a medium conductance as T(E)= 1, and Tetracene and Dibenzo coronene possess a high conductance with T(E)= 2. Low, medium and high values were elucidated according to the energy gap (E_g) and E_g gaps are strongly dependent on the number of aromatic rings (NAR) in the PAHs derivative. This study also suggests that any PAH molecules to be a conductor if E_g<0.20 eV. A linear relationship between the conductance and number of aromatic rings ( G∝NAR), was found and conductance follow the order G(Benzene,1NAR) < G (Anthanthrene, 4 NAR) < G (Dibenzo coronene, 9 NAR). The proposed study suggests a relevant step towards the practical application of molecular electronics and future device application