Density Functional Theory Calculations of the Stacking-Dependent Optoelectronic Properties of 2D GeSe/SnS Heterobilayers: Implications for Photovoltaics

Manipulation of interlayer interaction in nanoscale can effectively modulate the electronic and optical properties of layered materials, which can find photovoltaic applications when it is coupled with the in-plane or out-of-plan polarization. Here, based on in-plane ferroelectric 2D GeSe/SnS heterobilayer, we found that the optoelectronic properties can be well modulated by the interlayer stacking patterns from the density functional theory (DFT) simulations, where the ferroelectric ground states, electronic bandgaps and optical adsorptions are highly dependent on the relative interlayer configurations. Comparing with the homogeneous counterparts, the modulations are more significant due to the presence of vertical polarization. As a result, the power conversion efficiency of the heterobilayer increases from 13.4% to 22.8% by interlayer sliding. These findings provide feasible strategies to optimize the photovoltaic performance of 2D nanomaterial-based solar cells.