Keywords: 
• (TiO2)12量子环 /
• 密度泛函理论 /
• 过渡金属化合物掺杂 /
• 能隙

Abstract: In this paper, we have designed a new (TiO2)12 quantum ring structure and studied its geometry, average binding energy, and the electron density distributions using the generalized gradient approximation (GGA), which is based on the density functional theory (DFT) with the first-principles calculations. This new quantum ring structure is doped with transition metal compounds MoS2, MoSe2, MoTe2, WS2, WSe2 and WTe2 respectively, to modify its properties. Thus we can calculate and analyze their geometrics and electronic properties (such as average binding energies, energy levels, electronic density of states and the HOMO-LUMO electron density distributionsatc). We find that the (TiO2)12 quantum ring with a diameter of 1.059 nm seems to be of a two-dimensional structure with a center symmety which ensurs it a stable structure. In addition, the HOMO-LUMO orbital electron density in the quantum ring distributes evenly, and its energy gap is 3.17 eV which is very close to the experimental value of TiO2 semiconductor materials (3.2 eV). The energy gaps decrease substantially after introducing the transition metal compounds into the quantum ring. Among these results, the ring doped with WTe2 has the smallest energy gap (0.61 eV), and that with MoTe2 has the biggest energy gap (1.16 eV), but it is still smaller by about 2 eV than that of the (TiO2)12 quantum ring. Furthermore, other doping results have energy gap variation around 1 eV. The TiO2 clusters with this energy gap could make use most of the solar energy and so expand applications of TiO2.