Tandem Photovoltaics from 2D Transition Metal Dichalcogenides on Silicon

The demand for high-efficiency photovoltaic systems necessitates innovations that transcend the efficiency limitations of single-junction solar cells. This study investigates a tandem photovoltaic architecture comprising a top-cell with a transition metal dichalcogenide (TMDC) superlattice absorber and a bottom-cell of crystalline silicon (c-Si), focusing on optimizing the light absorption and electrical performance of the combined structure. Through the transfer matrix method and electrical simulations, we optimized the geometry of the superlattice, determining that a six-layer MoSe2 configuration with a 40 nm SiO2 antireflective layer maximizes photon absorption while mitigating additional weight and preserving the cell's structural integrity. The results show that the optimized TMDC superlattice significantly improves the power conversion efficiency (PCE) of the tandem design to 30.94%, an increase of 7.66% over the original single-junction c-Si solar cell's efficiency. This advancement illustrates the potential of TMDC materials in next-generation solar cells and presents a promising avenue for the development of highly efficient, tandem photovoltaic systems vis van der Waals integration of the to-cell on Si.