Basic Structure and Band Gap Engineering: Theoretical Study of GDYs

The original structure of graphdiyne (GDY) was proposed as a large molecular one. This is unlike our concept of material design today where we aim at finding an advanced material with a two-dimensional, layered, superlarge cavity structure. Arising from the abundant chemical bonds, large specific surface area, wide interplanar distance, high carrier mobility, good electrical conductivity, excellent chemical stability, and unique porous structures, GDY possesses excellent electrical, mechanical, optical, magnetic, and thermal properties. The band gap of GDY is calculated to be 0.44 eV at the local density approximation level and is noticeably increased to 1.10 eV at the GW level. The properties of GDY are probably superior to silicon because it has the direct band gap characteristics, which is quite appropriate for the semiconductor and optoelectronic devices.