Impact of the Interface Stacking and Composition of Janus Transition Metal Dichalcogenide Bilayers on the Solar Power Conversion Efficiency

Janus transition metal dichalcogenides hold great promise for achieving highly efficient solar cells. Therefore, the MoXY and WXY (X, Y = S, Se, Te; X ≠ Y) monolayers are examined using first‐principles calculations to identify candidates with direct bandgap. A systematic analysis in terms of the interface stacking and composition of bilayers constructed of these monolayers is performed. Out of the 40 studied cases, 12 cases exhibit a direct bandgap with type‐II band alignment and therefore are explored in detail. It is discovered that the composition (for the same stacking) can strongly enhance the power conversion efficiency, while the stacking (for the same composition) has minor effects.