Electrical Conductance and Diode-Like Behavior of Substituted Azulene

Nonequilibrium Green's function approach combined with density functional theory has been used to study electrical conductance of amino and cyano substituted azulene. The I-V curves show an increase in conductance when the amino groups exist at the 1,3 centers of the azulene rings and the cyano groups at the 4,8-postion. A modest current rectification ratio of about 2 was reported for substituted 2,6-azulene dithiolate, while the value increases to 3-5 when bridging azulene through the 2,7-position based on the presence or absence of substituents and their positions. Diode-like behavior could be noticed in 1,3-azulene dithiolate when it is substituted with electron donors such as amino group at carbons 4 and 8 or when replacing the 2,4,6,8-CH groups by nitrogen atoms.