Preparation And Photoelectric Properties Of Lead-Cesium Halide Perovskite Quantum Dots Encapsulated By Conducting Polymer

All-inorganic perovskite quantum dots have high light absorption coefficient,narrow emission spectrum,high photoluminescence quantum yield,adjustable composition and size,adjustable emission spectrum,so it has attracted a lot of attention from many scientific researchers in a very short time,and has been used as a hot spot for optoelectronic devices and luminous display materials.Although it has good potential in the fields of lasers and light-emitting diodes,its poor stability has always been one of the major bottlenecks restricting its development and industrial application.The main reason for the poor stability is that it is extremely sensitive to water and oxygen in the air.This thesis adopts the method of encapsulating all-inorganic perovskite quantum dots with conductive polymer to prepare composite materials,which obviously improves the stability of all-inorganic perovskite quantum dots in water.The main research contents are as follows:1.In this paper,CsPbBr3 all-inorganic perovskite quantum dots were synthesized by a thermal injection method.The structure of CsPbBr3 QDs was characterized by XRD,TEM,PL and other analytical methods.The characterization results show that the perovskite quantum dots have an orthorhombic phase structure and have good crystallinity and monodispersity.The QDs show a high absorption rate in the ultraviolet-visible region,and exhibit obvious exciton absorption characteristics.Moreover,the QDs have a sharp fluorescence emission spectrum,with a half-peak width as low as 19 nm,and a forbidden band width of 2.31 e V2.The photocatalytic oxidation method is used to encapsulate CsPbBr3 QDs with the conductive polymer PPy.PPy is not only an excellent hole transport material,but also very stable in air.PPy can not only effectively improve the separation efficiency of carriers,but also form a protective layer to encapsulate perovskite quantum dots,thus greatly improving the stability of quantum dots in water.TEM analysis results show that CsPbBr3 QDs is successfully embedded into the polymer.Infrared spectroscopy studies show that the characteristic peaks of functional groups on the surface of CsPbBr3 QDs-PPy are consistent with those of PPy,indicating that PPy was successfully formed by the photocatalytic oxidation method.The photocurrent results show that encapsulating with PPy can effectively improve the carrier separation efficiency.After immersing the composite material in water for 30 days,the phase of the composite material remained basically unchanged,indicating that this special structure can effectively protect quantum dots.3.In order to further improve the charge separation efficiency of CsPbBr3 QDs and improve its performance in the field of optoelectronics,CsPbBr3 QDs was encapsulated with PANI polymer through a photocatalytic oxidation method.TEM results show that CsPbBr3 QDs are encapsulated in the polymer matrix.Infrared spectroscopy studies show that the characteristic peaks of functional groups on the surface of CsPbBr3 QDs-PANI match the characteristic peaks of PANI,indicating that PANI is successfully formed by the photocatalytic oxidation method.The photocurrent results show that encapsulating with PANI can greatly improve the separation efficiency of carriers,and effectively inhibit the recombination of photogenerated electrons and holes.