Performance Optimization Of Mesoporous And Planar Perovskite Solar Cells Under Atmospheric Conditions

Organic-inorganic hybrid halide perovskite materials occupy excellent optical and electrical properties,for examples,long-range carrier diffusion length,low exciton binding energy,and high extinction coefficient,easily fabricated in the air by two-step method.These advantages have attracted widespread attention of researchers.For now,the energy conversion efficiency of the battery has been improved to 25.2%,which is comparable to commercial crystalline silicon solar cel s.Most investigator complete the assemble process of solar cell in a low-humidity,inert atmosphere,for instance,glove box.The stability of the perovskite battery obtained in this way is general y low,which also greatly increases the cost of solar cel.In order to reduce the assembling cost of solar cel,this article focuses on the assembling process of hole transport layer-free mesoporous perovskite solar cells based on carbon electrodes and planar perovskite perovskite solar cel.After a series of investigation,the efficiency of mesoporous perovskite solar cell based on carbon electrodes was increased to 14.5%,and the efficiency of planar perovskite solar cel s was increased to 18.77%.The specific research contents are listed as follows:1.The mesoporous Ti O₂ is applied as a scaffold layer.MAPb I₃ perovskite film is obtained by a two-step reaction method under the air condition.The conductive carbon film formed by the doctor blade method is used as a carbon electrode.Thus,the structure of perovskite solar cel s is FTO/Ti O₂/MAPb I₃/C.The average energy conversion efficiency of this type of solar cell is only 12.27%.In this structure,MAPb I₃perovskite can only absorb incident light with wavelength less than 775 nm,and the absorption capacity of incident light,especially long-wavelength light of 500 nm-800nm is insufficient.Thus,the short-circuit current density of the battery is limited.In order to solve this shortcoming,we synthesized hexagonal Na YF₄:Yb³⁺,Tm³⁺particles with upconversion effect by hydrothermal method.In order to synthesize Na YF₄:Yb³⁺,Tm³⁺@Si O₂ core-shell structure,the surface of upconversion particles is hydrolyzed with tetraethyl orthosilicate to form a tight coated layer of Si O₂.The mixture of Na YF₄:Yb³⁺,Tm³⁺@Si O₂ and Si O₂ was introduced as the insulating layer of the perovskite solar cel.The upconversion particles can absorb near infrared light and convert to visible light,the core-shell structure of large particles can enhance the ability of the mesoporous layer by scattering effect.The absorption of incident light of perovskite layer was improved accordingly.Through optimizing the ratio of up-conversion core-shell structure,the short-circuit current density and fill factor of the perovskite solar cell have been improved,and the power conversion efficiency is achieved to 14.5%.2.In order to further improve the efficiency of the perovskite cel,the mesoporous Ti O₂ was substituted by a Sn O₂ film spin-coated on the FTO substrate as an electron transport layer in the air condition,and the MAPb I₃ perovskite layer was substituted by FA/MA/Cs ternary perovskite material.Then Spiro-OMe TED was introduced onto the surface of perovskite layer as hole transport layer.The carbon electrode was substituted with Au formed via thermal evaporation,which forms a solar cell with structure of FTO/Sn O₂/perovskite/Spiro-OMe TED/Au.The average energy conversion efficiency is 16.5%.Trimethoxy-mercaptopropylsilane（MPTMS）was applied to passivate the Sn O₂ film.By adjusting the passivation processing time,we successfully improved the battery efficiency to 18.77%.After the passivation treatment of MPTMS,the surface defects of the Sn O₂ film are reduced,and the recombination of the charge at the interface is suppressed.In addition,the residual lead iodide at the interface is eliminated,and the quality of the perovskite film is improved,accordingly.The repeatability of the perovskite solar cell is also improved.