Study On Simulation Optimization And Preparation Technology Of Perovskite Solar Cells

Perovskite Solar Cells?PSCs?have made great achievements after nearly eight years of development.At present,the power conversion efficiency?PCE?of organic leaded halide PSCs has exceeded 22.1%based on spiro-OMeTAD Hole Transport Material?HTM?.And the certified highest PCE of large area?>1 cm²?PSCs has reached 19.6%.However,most of high-efficiency PSCs need using organic Spiro-OMeTAD materials as HTM,which are expensive and has poor stability.Moreover,noble metal such as Au or Ag is used as the back electrode,which requires high vacuum equipment.Therefore,in order to further reduce the production cost of PSCs and improve the PCE,it is necessary to choose cheap and stable HTM materials and excellent conductive and printable back electrode materials.At the same time,it is also necessary to optimize the preparation process of PSCs.Aiming at the above problems,two aspects-the theoretical simulation and experimental preparation of PSCs are carried out in this thesis.Theoretically,the electronic structure and optical properties of CH₃NH₃PbI₃ and CsGeI₃ are calculated by the first-principle method,which will provide the related physical parameters for the following device simulation.Then,planar heterojunction PSCs with carbon as electrode and CuI/NiO or CsGeI₃ as HTM are simulated by AFORS-HET software.The influences of light absorption layer,CH₃NH₃PbI₃/HTM interface and HTM on the solar cell performances are discussed.The results show that the best PCE is close to 23%for the two PSCs,and that the performances of the two PSCs are close to that of the PSCs with spiro-OMeTAD as HTM.This indicates that both CuI/NiO and CsGeI₃ can be used as an effective HTM which can be applied in the CH₃NH₃PbI₃ PSCs to replace expensive spiro-OMeTAD.While if the production process and the preparation cost are considered,the PSCs with CsGeI₃ as HTM will have better application prospects.Experimentally,the performances of PSCs are compared and analyzed for four different cleaning processing.It is found that the performance of the PSCs is the best after both trichlorethylene and UV light treatments on FTO substrate surface.Based on these,the influences of TiCl₄ solution treatment on TiO₂ dense layer and TiO₂porous layer on the performances of PSCs are investigated.It is found that the proper concentration TiCl₄ solution can modify layer crack in the surfaces of TiO₂dense layer and TiO₂ porous layer,and that the hydrolysis of TiCl₄ can further modify the micro-voids on the interface of the dense layer and porous layer,improving the films quality.The maximum PCE of PSCs treated with TiCl₄ solution can be increased about 18%than those of untreated samples.Based on the above optimization processes,the preparation of PSCs carbon electrode is further studied.The Ag nano particles and/or 1500?carbide needle coke are added in conductive carbon paste using isopropanol or chlorobenzene as organic solvent.It is found that the performance of PSCs cannot be improved by using isopropanol as an organic solvent for the carbon paste.But by using chlorobenzene as organic solvent of the carbon paste included Ag nano particles and needle coke,the performance of the PSCs can obviously be improved,and the PCE reaches to 9.68%.