Modeling heterojunctions: a computational chemistry perspective

The design of heterojunction photocatalysts with enhanced photocatalytic performance is a key challenge. Computational chemistry is a valid strategy to access, with atomistic details, the nature of heterojunction-based materials. In this review, we revise and recall a series of important modeling aspects to account for in the modeling of heterojunctions, such as structural models (including lattice mismatch), band offsets, and interface polarization. Lattice mismatch is essential to be considered to avoid spurious effects. Band offsets determine the relative positioning of the band edges, which in turn indicates the way photogenerated charge carriers prefer to move. The charge polarization has an effect on efficient charge separation which instructs the unidirectional charge migration through the preferential migration path of photogenerated charge carriers. In general, we describe general concepts for designing heterojunction photocatalysts. Drawbacks and potential prospects are discussed to help the field in creating more effective photocatalysts.