Tandem Photovoltaics from 2D Transition Metal Dichalcogenides\non Silicon

The demand for high-efficiency photovoltaic\nsystems necessitates\ninnovations that transcend the efficiency limitations of single-junction\nsolar cells. This study investigates a tandem photovoltaic architecture\ncomprising a top-cell with a transition metal dichalcogenide (TMDC)\nsuperlattice absorber and a bottom-cell of crystalline silicon (c-Si),\nfocusing on optimizing the light absorption and electrical performance\nof the combined structure. Through the transfer matrix method and\nelectrical simulations, we optimized the geometry of the superlattice,\ndetermining that a six-layer MoSe<sub>2</sub> configuration with a\n40 nm SiO<sub>2</sub> antireflective layer maximizes photon absorption\nwhile mitigating additional weight and preserving the cell’s\nstructural integrity. The results show that the optimized TMDC superlattice\nsignificantly improves the power conversion efficiency (PCE) of the\ntandem design to 30.94%, an increase of 7.66% over the original single-junction\nc-Si solar cell’s efficiency. This advancement illustrates\nthe potential of TMDC materials in next-generation solar cells and\npresents a promising avenue for the development of highly efficient,\ntandem photovoltaic systems vis van der Waals integration of the to-cell\non Si.