Study On Four Terminal Perovskite/Silicon Heterojunction Solar Cells

With the continuous progress of solar cell technology,the conversion efficiency of traditional silicon solar cells has been very close to the theoretical limit efficiency,and it is difficult to make a big breakthrough.Tandem solar cells consist of two or more sub-cells with complementary absorption spectra stacked in series or parallel to absorb different photons through different band gaps so as to improve the utilization rate of photons.The common tandem cell structure is the upper end of the perovskite cell as the top sub-cell,the bottom of the silicon solar cell as the bottom sub-cell.According to the connection mode of upper and lower batteries,the tandem solar cell can be divided into two-terminal tandem solar cell,three-terminal tandem solar cell and four-terminal tandem solar cell.In contrast to the other two types of tandem solar cells,four-terminal tandem cells are photocoupled and do not require current matching.The upper and lower cells have their own two independent terminals,so they can be operated and optimized separately.Therefore,this paper focuses on the study of four-terminal laminated cells.Since the upper and lower cells do not affect each other.Specific work contents are as follows:1.Using the simulation software AFORS-HET to simulate heterojunction solar cells,the understanding of the structure and characteristics of heterojunction solar cells was deepened in the simulation process,the structural parameters of the battery were optimized,and the conversion efficiency was 26.51%,the fill factor was 85.67%,the open circuit voltage was 0.7713V,and the short-circuit current was 40.89mA/cm~2Heterojunction solar cells.Using the simulation software SCAPS-1D to simulate perovskite solar cells.Perovskite solar cells with a conversion efficiency of 19.53%,filling factor of 82.4%,short-circuit current of 24.72mA/cm~2 and an open-circuit voltage of 1.046V were designed.2.The preparation process of heterojunction solar cells was studied experimentally.The effects of RF power of PECVD and doping concentration of borane on the performance of heterojunction solar cells during the depositation of p-a-Si:H layer were explored,and the deposition process with RF power of 80W and borane doping concentration of 1.5%was determined.Subsequently,the process conditions for depositing the TCO layer were explored,and the optimal process was determined when the deposition time was 30min,the deposition temperature was 100℃,the doping ratio of the target material was 2%,and the annealing time was 2h.After optimizing the process,the conversion efficiency of the heterojunction solar cells was 12.58%,the filling factor was 74.23%,the short-circuit current was 32.31mA/cm~2,and the open-circuit voltage was0.67V.3.The preparation process of perovskite solar cells was experimentally studied.First,the preparation process of HTL was studied,and it was found that the battery had the best performance when the homogenizer speed was 4000r/min and the annealing temperature was 160℃.Then,the preparation process of perovskite layer was studied,and when DMSO:DMF=1:4,annealing temperature was 100℃,and chlorobenzene drop-addition time was 8s,the perovskite at this time had the best surface morphology and the best performance after preparation into batteries.Finally,the preparation process of the ETL was studied,and it was determined that when the speed of the homogenizer was5000r/min,the prepared battery had the highest conversion efficiency.Through continuous experimental exploration and process optimization,the conversion efficiency of the perovskite solar cells prepared was 13.64%,the short-circuit current was22.51mA/cm~2,the open-circuit voltage was 0.94V,and the filling factor was 64.24%.4.Finally,the preparation of four-terminal tandem solar cells was completed,and in view of the problem that the gap between the upper and lower sub-cells of the four-terminal tandem solar cell would affect the cell efficiency,an intermediate matching layer was proposed to be inserted in the middle to improve the efficiency,and a four-terminal tandem solar cell with an air gap and a four-terminal tandem solar cell containing PDMS as the intermediate matching layer were prepared respectively.The efficiency of the prepared quadrendent laminated cell with air gap was 16.56%,and the efficiency of the quadrendic laminated cell with PDMS as the intermediate matching layer was 18.22%.