Ordered Semiconducting Nitrogen-Graphene Alloys

Abstract

The interaction between substitutional nitrogen atoms in graphene is studied by performing firstprinciples calculations. The effective nearest-neighbor interaction between nitrogen dopants is found to be highly repulsive because of the strong electrostatic repulsion between nitrogen atoms. This interaction prevents the full nitrogen-carbon phase separation in nitrogen-doped graphene. Interestingly, there are two relatively stable nitrogen-nitrogen pair configurations, whose stability can be attributed to the anisotropy in the charge redistribution induced by nitrogen doping. We reveal two stable, ordered, semiconducting N-doped graphene structures, C 3 N and C 12 N, through the cluster-expansion technique and particle-swarm optimization method. In particular, we show that C 12 N has a direct band gap of 0.98 eV. The heterojunctions between C 12 N and graphene nanoribbons might be a promising basis for organic solar cells.

Single layer of MX3 (M = Ti, Zr; X = S, Se, Te): a new platform for nano-electronics and optics

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An effective structure prediction method for layered materials based on 2D particle swarm optimization algorithm

“…The method has been successfully applied in predicting crystal structures for various high-pressure systems including semiconducting phase of lithium, 16 and the single layer 2D structures. 22,23 The 2D materials are not necessarily planar. Their atomic layers may buckle in the perpendicular direction.…”

How Much N-Doping Can Graphene Sustain?

“…49,50 In many applications, the limit of the N doping concentration in g-NG is important for both basic research and practical uses; however, it has not been found yet. Only isolated two-dimensional CN alloys were considered previously, such as C 12 N and C 3 N, 12 which are shown as smaller points on the diagram in Fig. 1, along with other two-dimensional BCN alloys considered theoretically.…”

“…Smaller circles show other two-dimensional BCN systems considered previously. 3,[12][13][14][15][16][17][18][19][20] Mixing energies of the 2D carbon-nitrogen alloy were obtained using the cluster expansion (CE) method. 51 …”