Research On Perovskite/Silicon Tandem Solar Cells

It is well known that the efficiency of single-junction solar cells is limited by its bandgap.The tandem solar cells combine the materials with different bandgaps so as to achieve wide absorption spectrum as well as high open circuit voltage,and thus high efficiency.Crystalline silicon solar cells have the advantages of stable performance and mature manufacturing process.The perovskite solar cells have excellent optoelectronic properties and low manufacturing cost.The combination of perovskite and silicon solar cells will further improve the efficiency of silicon solar cells.In this thesis,the perovskite/silicon tandem solar cell with a three-terminal structure is proposed,and its performance parameters are compared with those of traditional twoterminal and four-terminal tandem cells.The factors affecting its performance are analyzed.The research contents are as follows:（1）Two-terminal,three-terminal and four-terminal perovskite/silicon tandem solar cell models were established using the semiconductor simulation software TCAD.The conversion efficiencies of these tandem cells are compared,and the advantages of the three-terminal perovskite/silicon tandem cells are proved.The thickness influence of the perovskite absorber layer,the carrier lifetime of the silicon cell,the surface recombination rate and other factors on the performance of the cell were analyzed.A three-terminal tandem solar cell with sub-cell perovskite efficiency of 21.56%,sub-cell silicon efficiency of 6.56%,and a total efficiency of 27.12% was achieved.（2）An interdigitated back contact solar cell（IBC）with an efficiency of 12.88% was fabricated by standard CMOS processing technique,including photolithography,high temperature diffusion and thermal evaporation.A perovskite cell with an efficiency of12.08% was fabricated by using solution spin coating and thermal evaporation.The pretreatment of silicon wafers and the fabrication process of perovskite thin films were optimized.（3）The tandem solar cell was formed by making the sub perovskite solar cell on top of the sub IBC cell by spin coating and evaporation.The conversion efficiencies of the sub perovskite cell and the sub silicon cell were measured to be 0.34% and 3.75%,respectively,leading to the total efficiency of the tandem device was 4.09%.