Numerical Investigation of Perovskite/Silicon Heterojunction Tandem Solar Cell with a Dual-Functional Layer of MoO.

This study proposed a novel perovskite/silicon heterojunction (SHJ) tandem device structure without an interlayer, represented as ITO/NiO/perovskite/SnO/MoO/i-a-Si:H/n-c-Si/i-a-Si:H/n-a-Si:H/Ag, which was investigated by Silvaco TCAD software. The recombination layer in this structure comprises the carrier transport layers of SnO and MoO, where MoO serves dual functions, acting as the emitter for the SHJ bottom cell and as part of the recombination layer in the tandem cell. First, the effects of different recombination layers are analyzed, and the SnO/MoO layer demonstrates the best performance. Then, we systematically investigated the impact of the carrier concentration, interface defect density, thicknesses of the SnO/MoO layer, different hole transport layers (HTLs) for the top cell, absorption layer thicknesses, and perovskite defect density on device performance. The optimal carrier concentration in the recombination layer should exceed 5 × 10 cm, the interface defect density should be below 1 × 10 cm, and the thicknesses of SnO/MoO should be kept at 20 nm/20 nm. CuSCN has been found to be the optimal HTL for the top cell. When the silicon absorption layer is 200 μm, the perovskite layer thickness is 470 nm, and the defect density of the perovskite layer is 10 cm, the planar structure can achieve the best performance of 32.56%. Finally, we studied the effect of surface texturing on the SHJ bottom cell, achieving a power conversion efficiency of 35.31% for the tandem cell. Our simulation results suggest that the simplified perovskite/SHJ tandem solar cell with a dual-functional MoO layer has the potential to provide a viable pathway for developing high-efficiency tandem devices.