부산대학교 도서관

Owing to their importance of quantum dot-sensitized solar cells (QDSSCs), a novel system with atomically precise MgO nanoclusters atop of the TiO2(001) surface was designed on the basis of first-principles studies. In the present study, the MgO-QD/TiO2heterojunction was designed for several geometries, more specifically the 2 × 2 × 2 MgO/TiO2in the (001) plane, using first-principles calculations. In this work, the normalized adsorption and aggregation energies, partial density of states, alignment of the QD-HOMO and LUMO values, optical absorption characteristics, electron injection, and carrier recombination rates are all thoroughly examined. The 2 × 2 × 2 MgO-QD exhibits the highest adsorption stability with low propensity for aggregation as well as the best light absorption efficiency. Nonadiabatic molecular dynamics simulation method combined with time-dependent density functional theory indicates that the electron injection rate and recombination rate favor the solar cell application due to suitable spatial overlap and separation of charge densities, and particularly, 2 × 2 × 2 MgO-QD/TiO2heterojunction is projected to exhibit the highest electron injection efficiency. We hope our computationally predicted MgO-QD/TiO2(001) heterojunction system might provide direction for designing new quantum dot-sensitized heterojunction materials for solar cell applications.