Study On The Performance Of Planar Solar Cells Based On BaTiO₃ Modified Electron Transport Layer

Since the long-term development of society,people have increasingly consumed non-renewable energy sources,causing a series of problems such as energy crisis and environmental pollution.People urgently need new clean energy to replace non-renewable energy.Solar energy is the most common safe,pollution-free and low-cost renewable energy source.At present,among the many photovoltaic technologies that can directly convert the solar light energy into electrical energy,perovskite solar cells are the research hotspot of the majority of scientific researchers.Perovskite solar cells have developed rapidly in recent years,and their photoelectric conversion efficiency has exceeded 24%in just ten years.In perovskite solar cells,perovskite CH₃NH₃PbI₃?MAPbI₃?with lower recombination rate,stronger light absorption,bipolar charge transport and long carrier diffusion length becomes perovskite solar cells photosensitized Agent.Titanium dioxide?TiO₂?with good band gap matching and good photoelectrochemical stability is widely used as an electron collection and transport material.The efficiency and stability of perovskite solar cells depend not only on good light-absorbing materials and suitable electron?hole?transport materials,but also on the interface between light-absorbing materials and electron?hole?transport materials.This paper focuses on improving the interface between the electron transport layer?ETL?/perovskite light absorption layer and improving the quality of the perovskite film.The dense TiO₂?bl-TiO₂?film was immersed in barium nitrate solution,and then dried and annealed to form a BaTiO₃ nano-film on the surface of the bl-TiO₂ film.The effect of the immersion period on the performance of planar perovskite solar cells was discussed.The prepared inorganic perovskite BaTiO₃ as seed crystals promotes the rapid nucleation and growth of organic-inorganic perovskite MAPbI₃.The study found that the MAPbI₃ grains showed a larger size in the scanning electron microscope?SEM?,and at the same time achieved a higher light absorption and fill factor?FF?.The main contents of this paper are as follows:?1?Dissolve lead iodide?PbI₂?and iodomethylamine?MAI?in N,N-dimethylformamide?DMF?and dimethyl sulfoxide?DMSO?mixed solvent?DMF-DMSO?to prepare MAPbI₃ precursor solution,spin-coat the precursor solution on bl-TiO₂ thin film by one-step spin coating method and heat-treat it MAPbI₃light-absorbing layer.By adjusting the volume ratio of DMF-DMSO,the effect on the crystallinity,morphology and battery performance of MAPbI₃ was studied.When the volume ratio of DMF-DMSO is 4/6,the MAPbI₃ grains grow completely and the grain boundaries are clear,and the efficiency of the perovskite solar cell produced by this method reaches 15.03%.?2?Immerse the bl-TiO₂ film in an aqueous solution of barium nitrate?Ba?NO₃?₂?,dry and anneal to obtain a BaTiO₃ modified bl-TiO₂ electron transport layer.It is used to modify the interface between ETL and MAPbI₃,so that the photovoltaic performance of the battery is improved.X-ray diffraction and X-ray photoelectron spectroscopy analysis proved that BaTiO₃ film was formed on the surface of bl-TiO₂.In addition,the presence of perovskite-type BaTiO₃ nanocrystals promotes rapid nucleation and growth of MAPbI₃,making its grain size larger.The photocurrent density-voltage curve?J-V curve?test was performed on the battery based on bl-TiO₂/BaTiO₃,and the photoelectric conversion efficiency of the perovskite solar cell was 17.71%when immersed in the fourth cycle.