Investigation On Terahertz And Ultrafast Characteristics Of Two-dimensional R-P Hybrid Perovskite

In recent years,organic-inorganic hybrid perovskite materials have been widely used in the field of terahertz modulators due to their intentional optoelectronic properties.However,environmental stability is low and it is difficult to achieve commercial production.The two-dimensional Ruddlesden-Popper(RP)type organic-inorganic perovskite inserts hydrophobic organic amine ions into the voids of the traditional three-dimensional perovskite inorganic layer stacking,which not only improves environmental stability,but also has good optical properties,Which gives it a better development prospect.However,there is not much research in the field of terahertz regulation.In this thesis,spin-coating method is used to prepare two-dimensional perovskite film,and its terahertz characteristics and ultrafast characteristics are studied and analyzed,and the relevant photoelectric parameters are obtained.The main research contents include:First,preparation of 2D perovskite(PEA)₂(MA)₂Pb₃I₁₀ thin film by one-step spin coating method,using X-ray diffraction,scanning electron microscopy,ultraviolet-visible light absorption spectroscopy and photoluminescence and other characterization techniques,explored anti-solvent and annealing The impact of important technological processes on the performance of the film.The stability of the two-dimensional perovskite was studied,and it was found that the environmental stability of the two-dimensional perovskite was greatly improved compared to the three-dimensional perovskite material.Then,using the terahertz time domain system to explore the terahertz characteristics of 2D perovskite films based on quartz and silicon substrates.It was found that the bandwidth modulation of 0.5-1.5THz based on the quartz substrate can be achieved,and the modulation depth can be achieved 10%.The two-dimensional perovskite film based on the silicon substrate can achieve 30%modulation depth,and the modulation bandwidth is 0.5-1.3THz.According to the measured transmission signal,obtain relevant optical parameters,such as refractive index,electrical conductivity,etc.Finally,we used optically pumped terahertz detection to study the ultrafast properties of two-dimensional perovskite films.The carrier decay process is fitted by a three-exponential formula,and the carrier transport mechanism is studied.It is found that the early recombination process?₁ is contributed by hot carriers,?₂ is mainly affected by exciton recombination,and?₃ is mainly defect-assisted recombination.The Drude-Smith model is used to fit the photoconductivity in different periods and obtain the relevant electrical parameters.