Preparation,Regulation And Application Of Nanoarray Structures On Perovskite Single Crystal Surface

In recent years,organometallic halide perovskite nanoarray structures have attracted much attention owing to their potential applications in polarized light,resolved X-ray imaging,light-emitting diodes,and lasers.Although processes such as dry and wet etching and vapor deposition can fabricate ordered patterned nanostructures,these methods often require complex fabrication steps and harsh fabrication conditions such as high vacuum,which greatly increase their large-scale the cost of the application.In contrast,the preparation of nanoarray structures by chemical solution method has the advantages of low cost,simple steps,and rapid preparation.However,due to the limited research on the nucleation mechanism and growth kinetics,the micro-nano structure arrays reported by chemical solution methods are often randomly oriented,and it is difficult to precisely control the uniform directional growth of the array structures in the large-area preparation process.These random distributions can seriously affect the optical and electrical properties of the array structure.Therefore,the controllable growth of nanoarray structures by chemical solution methods remains a great challenge.In this paper,the controllable epitaxial growth of low-dimensional nanoarray structures was realized on the surface of CH₃NH₃Pb I₃(MAPb I₃)single crystal perovskite by chemical solution method,and the growth kinetics and regulation mechanism were explored.The potential optical applications of this highly ordered oriented low-dimensional nanoarray structure in the fields of laser and anti-counterfeiting polarization are further demonstrated.The specific research contents are summarized as follows:1.Regulation of the growth direction of relative nanostructures in hydrated intermediate phase.We first prepared MAPb I₃single crystals using the inversion temperature growth method.By polishing,acid etching,and hydration pretreatment on the single crystals,a zero-dimensional hydrated intermediate phase structure layer was synthesized on the surface.We found that the nanostructures grown on the surface of the hydrated single crystals were aligned along the out-of-plane direction.Through further study of the growth process,we found that this out-of-plane growth is caused by the hydrated intermediate phase induce lead-iodine octahedral cage rearrangement.By changing the time of hydration pretreatment,we prepared a uniform and densely arranged monolayer water and hydrated intermediate phase structure on the surface of the single crystal,and then realized the growth of the nanoarray structure with controllable orientation.2.Regulation of concentration growth kinetics on growth morphology of nanostructures.On the basis of the water and mesophase regulating the growth direction of the array structure in the previous chapter,we further explored the factors that affect the morphology of the surface nanostructures.We found that a continuous transition of nanostructure morphology from nanosheets to nanorods can be achieved by varying the concentration of iodide phenethylamine in isopropanol.This morphological transition is the result of the combined effect of the concentration of phenylethylamine iodide on the nucleation rate and growth rate.Benefiting from the synergistic regulation of the growth direction and morphology of the hydrated intermediate phase and the concentration of phenylethylamine iodide,we successfully prepared low-dimensional perovskite nanoarrays with uniform orientation and controllable morphology on the surface of MAPb I₃single crystals.3.Optical applications of highly ordered nanoarray structures.Based on the preparation of highly oriented perovskite nanoarray structures in the previous chapter,we further explored their applications in the optical field.We first verified the amplified spontaneous emission phenomenon in the array structure,demonstrating its potential application in the field of lasers.After that,we carried out the polarization performance test,and its linear polarization rate was 0.45.Finally,through hydration treatment and growth kinetic regulation,we prepared a uniform large-area polarized array structure and used it for anti-counterfeiting polarized emission devices.The device fluorescence exhibited good angle-dependent characteristics,indicating its potential application value in the field of high-resolution encrypted imaging.