Superresolution Research Based On Perovskite Quantum Dots

Perovskite quantum dots have been gradually applied to various high-tech fields,such as various display systems,solar cell components,or fluorescent probes for fluorescence microscopes,due to their excellent monochromatism,high quantum efficiency,and the ability to achieve emission wavelengths in the full visible spectrum through composition adjustment.Among them,perovskite quantum dots as fluorescent probes are getting more and more attention from professionals in the field of biology and health care.If perovskite quantum dots are to be better used as fluorescent probes in related fields,the improvement of their optical resolution and the exploration of their optical properties after the improvement of their resolution are important problems to be overcome.The first is the way to improve the optical resolution.Due to the limitation and interference of diffraction limit,the maximum resolution of the traditional optical microscopy system represented by the confocal system is generally limited to more than 200nm.In recent years,stimulated emission depletion(STED)super resolution technology and perovskite quantum dots with received extensive attention of the personage inside course of study,because of the perovskite quantum dots have long fluorescence lifetime,the larger absorption cross section which can realize low depletion optical power of STED super resolution imaging,optical power depletion is low compared with the traditional dye molecules need 1 to 2 orders of magnitude,better able to avoid the high power laser conditions brought about by the application of quantum dot devices.Another concern is the super resolution case perovskite optical properties of quantum dots change,because the super resolution is implemented by the spontaneous radiation into stimulated radiation originally,and this part will be stimulated radiation filtered so as to realize the effect of the resolution,the spontaneous radiation into stimulated radiation will inevitably occur in the process of fluorescence lifetime,fluorescent flashing,single photon emission etc.The change of the optical properties,if can be a more thorough analysis of the physical principles,then the application of perovskite quantum dots provide invaluable advice.The main research work and innovation points of this paper are as follows:1.A super resolution scanning system combining the super continuous laser as the depletion light and the pulse laser as the excitation light and the confocal system was built.Through continuous improvement and optimization of the system,the in-situ super-resolution scanning imaging of CsPbBr3 perovskite quantum dots was realized by combining stimulated emission depletion technology and confocal technology,with the highest transverse resolution of 70nm.It not only realizes the in-situ super-resolution imaging of a single quantum dot in the scanning region,but also successfully realizes the elimination of excess fluorescence through optical imaging and optical property analysis,so that the region that cannot be distinguished as a single quantum dot can be clearly determined as the scanning effect of a single quantum dot.2.Stable CsPbBr3 perovskite quantum dots and CsPbI3 perovskite quantum dots samples suitable for this system were synthesized by Hot Injection method,and various optical properties and other physical properties of the samples were characterized.3.Using TCSPC(Time-Correlated Single Photon Counting)system,in the implementation of CsPbBr3 nanocrystals of super resolution imaging on the basis of the analysis of characteristics of the fluorescent flashing further change,found high power depletion of light to suppress the existence of the bright state proportion,and shorten the perovskite quantum dot fluorescent life,because of the stimulated emission make originally the exciton compound transformed into other non radiation composite ways.4.This system not only improves the single-photon emission efficiency of quantum dots with anti-bunching effect;In addition,the region where the single photon emission source could not be distinguished was successfully made.After superresolution microscopic imaging,the anti-bunching effect was shown,and the location of the single photon emission source was successfully distinguished.