Single-photon Emitting Properties Of Perovskite Cspbbr₃ Nanoplatelets

In recent years,the influence of size and shape on the optical properties of 2D nano-materials has gained growing interest.These excellent properties make 2D nano-materials promising for LED,lasing,photodetector applications,and especially the realization of single photon source.Single photon emitters with certainty and high indistinguishability play a central role in many photonic quantum technologies,such as optical quantum computing and quantum communication.So far,single-photon emission has been achieved in a variety of 2D nano-materials.Perovskite structure nanocrystals are a new type of nano-material with superior optical properties.It is most meaningful to manufacture 2D perovskite nanocrystals and realize single photon emitter in perovskite nanoplates(NPLs).In this thesis,we focus on the technique of synthesizing perovskite NPLs by wet chemical methods,and study the interesting single-photon emitting properties of single CsPbBr3 NPLs.In chapter II,we studied the synthesis of CsPbBr3 NPLs,including the wet chemical methods and shape control.The synthesis of nanoparticles using wet chemical methods require three components(precursors,ligands and solvent)and appropriate synthesis technique.Through a series of experiments,we finally found the suitable components and successfully synthesized nanocrystals by hot injection technique.By now,there are many ways to control the shape of the generated NPLs,such as ligands control,reaction time control and temperature control.In this thesis,we used the temperature control method and synthesized CsPbBr3 NPLs with outstanding optical properties.In chapter III,we studied the single photon emission of single CsPbBr3 NPLs,We isolated single CsPbBr3 NPLs and observed the second-order correlation function statistics by confocal scanning microscopy measurements.We found that some of the NPLs showed excellent single photon emission properties while many other NPLs did not.Further more,NPLs with different single photon emission properties are uniformly distributed.Through further research,we found that many single NPLs showed interesting optical properties,for instance,bimodal fluorescence peaks.After analyzing the fluorescent lifetimes separately,blinking on/off states of the double peaks,we confirmed that there are two different fluorescent mechanisms in single CsPbBr3 NPLs.