Study On Interlayer Exciton Regulation Of Two-dimensional Perovskite / Transition Metal Dichalcogenides Heterostructure

Interlayer excitons have important application value in the field of optoelectronics.Effective regulation of interlayer exciton is the basis of realizing its device function and improving device performance.The interlayer coupling of two-dimensional perovskite/TMDs heterostructures and the regulation of interlayer excitons remain to be studied.Based on this,the regulation methods and mechanisms of interlayer excitons in two-dimensional perovskite/TMDs heterostructures are studied in this dessertation.In this dissertation,the van der Waals heterojunction composed of two-dimensional perovskite（iso-BA）₂Pb I₄ and single-layer WSe₂ is taken as the main research object,and the strain is introduced by Si O₂ nano-pillar array to regulate its interlayer exciton.Under the action of nano pillars with a height of 80 nm and a diameter of 600 nm,the interlayer exciton peak has a blue shift of about 3.1 nm and a luminescence enhancement of about 2.8 times.The ratio of interlayer excitons to intralayer excitons also increases under the strain of pillars.It is mainly because the strain introduced by nano pillars reduces the interlayer spacing between（iso-BA）₂Pb I₄ and single-layer WSe₂,so as to enhance the interlayer coupling.This dissertation also studies the coupling between heterostructures under different stresses and the change process of exciton spectrum.With the increase of the height and the decrease of the diameter of the pillars,the interlayer coupling is further enhanced.Additional spin triplet interlayer excitons were observed under the strain of nano pillars with a height of240 nm and a diameter of 600 nm.Based on the experimental research,this dissertation further uses COMSOL multiphysical field simulation to simulate the deformation effect of strain on the material and the influence on the interlayer coupling of heterojunction.The simulation shows that the interlayer spacing of heterojunction is reduced by 2.8 nm under the action of nano pillars with height of 80 nm and diameter of 600 nm,which is consistent with the enhancement of interlayer coupling observed in the experiment.With the decrease of the diameter and the increase of the height of the nano pillars,the interlayer spacing further decreases,which is consistent with the experimental results.In conclusion,using the method of experiment and simulation,this dissertation realizes the fixed-point regulation of strain on the interlayer coupling of two-dimensional perovskite/TMDs heterojunction,and explores its regulation mechanism.It provides some guidance for realizing the efficient regulation of interlayer exciton in two-dimensional perovskite/TMDs and improving the performance of interlayer exciton devices.