Investigation Of Electromagnetic Properties And Phonon Coupling Performance Of Organic-inorganic Hybrid Perovskite

Organic-inorganic hybrid perovskite materials have attracted much attention due to their excellent light absorption ability and good carrier transport properties,and have a wide range of applications in the fields of solar cells,superconductivity,and photodetection.Ultrafast processes such as light absorption,photocarrier relaxation recombination,and charge transport in perovskite semiconductors are the main physical processes that affect their optoelectronic and electromagnetic properties.Metamaterials are artificially designed and prepared periodic structural materials that have a special response mechanism to electromagnetic waves in specific bands.They are widely used in the fields of metalens,negative refraction,and invisibility.Studies have shown that terahertz waves can resonate when transmitted in specific metamaterials,that is,there are strong field localization and field enhancement in the gap structure of metamaterials,which can provide conditions for the phonon coupling phenomenon of materials.In this paper,polycrystalline thin films of CH₃NH₃Pb I₃material were prepared by an economical and simple solution spin coating method,and the terahertz transmission properties and ultrafast properties of CH₃NH₃Pb I₃thin films were introduced.The metal metamaterials were prepared by lithography,deposition and lift-off,and combined with CH₃NH₃Pb I₃polycrystalline thin films to explore the phenomenon of strong phonon coupling in the terahertz band.The specific research contents are as follows:1.The organic-inorganic hybrid perovskite CH₃NH₃Pb I₃polycrystalline thin films were prepared by solution spin coating,and characterized by SEM,XRD,UV-Vis absorption spectroscopy and PL test.The effects of different processes on the crystallinity and optoelectronic properties of the samples were studied.On this basis,the influence of doping metal ions in the precursor solution on the perovskite film was studied,and the organic-inorganic hybrid perovskite film with high coverage and good crystallization was obtained by optimizing the process.2.CH₃NH₃Pb I₃thin films were prepared on high-resistance silicon substrates and quartz substrates,respectively,and the THz transmission characteristics of the two samples were tested using a standard THz time-domain system.That is,the tuning ability of the two samples for terahertz wave transmission was investigated under continuous laser pumping.In addition,the ultrafast performance of the perovskite film was tested by the ultrafast pump terahertz detection system,the relaxation process of the perovskite material was explained,and the change law of the photoconductivity of the perovskite material during the process was fitted.3.Periodic micron-scale metal metamaterials were fabricated on high-resistance silicon substrates by traditional micromachining techniques,and the effects of different process parameters(exposure energy and development time)on lithography patterns were investigated.By optimizing the fabrication process parameters,a pattern-standard metamaterial was successfully fabricated,and the terahertz transmission properties of the bare metamaterial and the metamaterial covered with perovskite films were tested respectively.On this basis,electromagnetic simulation software is used to establish a device model to simulate the terahertz transmission characteristics of perovskite metamaterials under different conditions,and to analyze the strong phonon coupling effect of perovskite metamaterials according to the changing laws of transmission characteristics.