Optical Properties And Applications Of Perovskite Quantum Dots

In recent years,perovskite as a new type of photoelectric material has attracted more attention.With the development of research,its research has gone from bulk materials to nano-materials,and finally to quantum dot materials.In terms of its structural formula,the perovskite material is composed of ABX₃ type.Its position is mainly CS⁺,B position is Pb²⁺,and X position is composed of halogen elements.In terms of electrical properties,perovskite material has excellent electrical properties,high electron mobility,broad absorption coefficient;in terms of optical properties,it has the advantages of high color purity,narrow luminescent half width,high luminescent quantum efficiency and so on.However,for perovskite materials,there are two main problems to be solved:?1?the stability of the materials is poor,especially easy to decompose in water,and the storage time in air is short;?2?the toxicity of lead ions,it is difficult to apply it to the actual industrial production.Therefore,this paper focuses on the above two issues for systematic research.As an excellent luminescent material,perovskite quantum dots have been widely used in lighting display,LED devices,photoelectric detection and other practical life.However,in order to make it widely used,its stability needs to be solved urgently.To improve the stability,we can start from the characteristics of the material itself or enhance its stability through later modification.In this part,the surface of perovskite is modified by silica,and the stability of quantum dots is improved by coating.Then,it is applied to white LED and cell imaging,and good results are obtained.The perovskite quantum dots were synthesized by heat injection method,and the high quality quantum dots were obtained by centrifugal precipitation.Then,by adding TEOS,ammonia,and isopropanol,stirring at room temperature,and finally by centrifugation and re precipitation,the perovskite QDs with good monodisperse silica coating were prepared.By controlling the amount of ammonia added,stirring time and temperature,the better coating materials can be obtained.Its stability has been greatly improved,and its optical properties remain unchanged.Finally,it is applied to white led to get a better lumen value,and it has a better imaging effect when applied to cell imaging.With the continuous improvement of people's awareness of environmental protection,the toxicity of lead ions has attracted great attention.For perovskite quantum dots,it is very important to solve the toxicity problem of lead ions.Therefore,in this part,the new perovskite quantum dot material is synthesized by substitution method,and the toxicity problem is solved by bismuth ion instead of lead ion.The synthesis of Cs₃Bi₂Br₉ perovskite quantum dots by low temperature method,and the synthesis of nontoxic perovskite quantum dots with excellent luminescent properties by changing the reaction temperature and the amount of alcohol.However,there is still a certain gap in optical properties compared with lead quantum dots.It has been widely accepted that the optical properties of quantum dots can be changed by doping rare earth ions.Therefore,the problem of red light loss in bismuth based quantum dots can be solved by Eu³⁺doped Cs₃Bi₂Br₉ perovskite quantum dots,and the quantum efficiency of luminescence can be improved to a certain extent.Finally,the obtained materials are applied to the detection of copper ions,and a better detection lower limit is obtained,which has a better practical application prospect.