Research On Optical Properties Of Semiconductor Quantum Rods-Noble Metal Nano Periodic Array

Semiconductor quantum rods(QRs),with the polarization emission and absorption characteristics,offers a promising platform for applications including liquid crystal display,polarization light source,photoelectric conversion,and other fields.To obtain the polarization characteristic,it is necessary to align them directionally on a large scale.Similar to the quantum dots,the quantum efficiency of QRs emitting fluorescence decreases with the decline of radiation decay rates,and the energy transfer of non-radiative channel is in a competitive relationship with fluorescence emission.Controlling the radiative and non-radiative channels of QRs is essential for realizing the practical application of QRs.Due to the enhancement effect of the local field by surface plasmon resonance(SPR),the coupling between metal nanostructures and QRs will produce some interesting phenomena,such as ultrafast electron transfer and local field enhancement of plasma.These characteristics can be used to control quantum efficiency.Therefore,it is significant to study the optical properties of the composite structure of QRs and noble metals.This thesis mainly studies the orientation and fluorescence regulation of Ag nanoparticle array on QRs theoretically,numerically,and experimentally.First,three important principles are analyzed base on theoretical analysis and formula derivation including 1)Fluorescence generation of the semiconductor nanocrystals;2)SPR of noble metal nanostructures and the control of fluorescence;3)Laser evanescent standing wave optical control assembly.Next,the evanescent standing-wave light field is built,and the silver nanoparticle array substrate was prepared by the light-controlled assembly method then compounded with QRs.The optical properties of the composite structure were tested.Due to the limitation of experimental conditions,only the optical characteristics of fluorescence quenching were tested.Compared with the QRs on the blank substrate,the fluorescence intensity of the composite device is quenched sharply and affected by the polarization state of the excitation light.When the polarization of the light is parallel to the direction of the Ag nanoparticle array,the quenching effect is most significant.The fluorescence emitted by the composite device has certain polarization characteristics.Finally,adjusting the distance from the Ag nano wire array,the enhancement and the quenching effect of the fluorescence intensity of QRs are studied by modeling in simulation software.The simulation shows that when the distance between the two is 14nm,the fluorescence is maximized.Therefore,by setting the distance reasonably,the control of radiative and non-radiative channels can be achieved.