The Theoretical Research Of Graphdiynes On Regulation Of Electronic Properties And Related Performances

As a new kind of carbon allotropes, graphdiynes have rich carbon bond, excellent stability and optoelectronic properties. Since y-graphdiyne has been successfully synthesized in 2010, researchers have done a lot of research work on graphdiynes about optoelectronic, energy storage and catalytic properties, but few studies have been reported of graphdiynes on regulation of electronic properties and related performances. In order to widely use graphdiynes in the field of electronics, regulating the electronic properties of graphdiynes by doping and electric field is very important.In this paper, the first-principles calculation based on density functional theory has been performed to investigate the optoelectronic properties of B-doped, N-doped and B-N co-doped of γ-, β-, α-graphdiyne, and the electronic properties of pristine and doped graphdiynes in presence of electric field have been studied, the main research conclusions are as follows:1、For all three graphdiynes, B atom is easier to replace the sp2 hybridized C atom on the 1# position, and N atom is easier to replace the sp hybridized C atom on the 2# position. The formation energy of N is less than B, which means graphdiynes are easier to form n-type semiconductor. With the increasing of B, N impurity concentration, the formation energy gradually increased, and system stability gradually decreased. For γ-, β-graphdiyne, the system gradually turned to be p-or n-type degenerate semiconductor with the increasing of B, N impurity concentration, and the bandgap gradually decreased. B-N co-doped is more likely to form adjacent doping form, with bandgap increased or decreased according to different doping bit. The a-graphdiyne produces a certain bandgap after doped, which improves the situation of zero bandgap. B-or N-doped can cause the redshift of optical absorption edge of γ-, β-graphdiyne, and the redshift is weakened with the increasing of doping concentration, B-N co-doped can cause the optical absorption edge red shift or blue shift. For the α-graphdiyne, different types of impurity can cause the redshift of the optical absorption edge.2、The electrostatic potential is broken and the charge is redistributed for all the graphdiynes systems in presence of electric field according to the giant stark effect. With the increasing of electric field strength, the bandgaps of γ-and β-graphdiyne show a decreasing trend, and the bandgap of (3-graphdiyne decreases more rapidly. The a-graphdiyne turns from zero bandgap to a direct bandgap semiconductor in the electric field, the bandgap shows an increasing trend.3、With the increasing of the electric field strength in different directions, the bandgaps of B-doped or N-doped graphdiynes do not appear uniform change trends, the electronic properties of the doped systems are strongly influenced by the direction of the electric field. The bandgap of B, N co-doped graphdiynes have a same change trends like pristine graphdiynes in presence of electric field, with the increasing of electric field strength, the bandgaps of B, N co-doped γ-, β-graphdiyne show a decreasing trends, and the bandgap of B, N co-doped a-graphdiyne shows a increasing or slowly decreasing trend.