The Mechanism Analysis Of Perovskite/P-type Silicon Heterojunction Perovskite Solar Cells

Application of p-type silicon in perovskite solar cells as the hole-transporting layer is a novel solution for the comprehensive optimization of the cost,efficiency and stability.However,the structure optimization and the selection of materials of this novel cell is lack.Therefore,this thesis focused on the modeling and further optimization of the p-type silicon perovskite solar cells,by using a semiconductor device simulator and taking the examples of the other perovskite solar cells as references.The parameters of the cell,such as the thickness,the doping concentration and other material characteristics of each layer were optimized.Further more,the impact of metal work function,defect density,carrier mobility,and band offsets on performance were also studied.Finally,the main problems of the experimental that need to be solved was analyzed.The main conclusions are as following:In the p-type silicon perovskite solar cell,TiO₂ is more suitable as the electron transport material,and its optimal N_D is 1×10¹⁸cm^-3,and the optimal thickness is 50nm.At the same time,with the use of CH₃NH₃PbI₃ as i layer,the solar cell get higher PCE and the optimal thickness of CH₃NH₃PbI₃ is 1um,the optimal N_D is 1×10¹³cm^-3.When the thickness of p-type silicon is between 200⁸00 nm,the p-type silicon perovskite solar cell get a higher PCE,and its optimal N_A=1×10¹⁹cm^-3.Based on the optimal structure and the optimal selection of the materials,the impact of work function of metal electrode was simulated and analyzed in this paper.When_M-rear=-4.8^-5.2eV and_M-front=-3.4^-4.2eV,a higher performance was obtained in the p-type silicon perovskite solar cell.In order to get a higher PCE,the impact of band offset of CH₃NH₃PbI₃/p-type silicon solar cells was simulated and analyzed here.When VBO=0.2⁰.4eV,the performance is almost saturate to the plateau and the PCE of 22.25%can be expected.However,when the electron affinity and band gap of the p-type silicon are adjusted to appropriate range,the performance is optimal and a higher PCE of 23.01%can be obtained.Finally,we tried to find out the problems that need to be solved in the experiment by our theoretical analysis.It is worthy of recognition that in the p-type silicon perovskite solar cell,using an interlayer of C₆₀ thin film through thermal evaporation would avoid the sputtering damage on the perovskite layer,and improve the performance.In addition,we conclude that the problems in the experiment mainly include the design of the structure,the selection of the materials,and the work function matching of the electrodes.