Preparation And Properties Of Organic-inorganic Hybrid Perovskite Nanocrystals Based On Lead Recovery

The earliest display technology in industry,the cathode ray tube?CRT?has reached the summit of scrapping.CRT glass contains lead,barium and other toxic substances,which can be harmful once discharged into the air.Over a long period of time,it has great potential to cause serious harm to the ecological environment and people's health.Organic-inorganic hybrid perovskite material CH₃NH₃PbX₃?X=Cl,Br,I?is a new type of material with quantum well structure.It has been widely used in many fields,such as light-emitting diodes,field-effect transistors and so on.Therefore,lead halide were prepared from lead compounds extracted from CRT,and then CH₃NH₃PbX₃?X=Cl,Br,I?materials were synthesized by using the lead halide.By reusing the lead resources,the life cycle of lead can be prolonged,and thus achieve the purpose of environmental protection.We further explore the controllability and stability of perovskite nanocrystals,and the main research was summarized as following:1.The lead compounds extracted from waste glass were converted into lead halide as raw materials for the preparation of PbBr or PbI,Lead halide were then used to synthesize CH₃NH₃PbX₃?X=Cl,Br,I?.The CH₃NH₃PbBr₃ and CH₃NH₃PbI₃ materials were characterized and analyzed by UV-vis,PL?Photoluminescence spectrum?and XRD?X-ray diffraction?.The synthesized PbBr or PbI have high purity.2.This chapter choosed the appropriate preparation method of CH₃NH₃PbBr₃nanocrystalline and explored the function of octylamine as a new capping molecule on CH₃NH₃PbBr₃ nanocrystalline.At the same time,the materials were characterized by PL,Abs?absorption spectrum?,TEM?Transmission electron microscope?and XRD.The results show that CH₃NH₃PbBr₃ with different sizes can be obtained by adjusting the amount of octylamine,and its luminescence wavelength can be adjusted in the range of 430-530 nm.3.To optimize the experimental scheme and explore the methods to improve the stability of CH₃NH₃PbI₃ nanocrystals,the effect of Methyl Methacrylate?MMA?on the stability of CH₃NH₃PbI₃ nanocrystals was investigated.The materials were analyzed by abs PL,XRD and SEM?scanning electron microscope?.The results showed that the stability of CH₃NH₃PbI₃ nanocrystalline could be improved under the optimized condition of 400?L MMA.The fluorescence duration was increased from 5 days to 12 days,and the material was mainly cubic phase.4.The quantum size effect of CH₃NH₃PbBr₃ nanocrystalline prepared with oleylamine as capping molecule was studied,and the mechanism of organic ligands were demonstrated.The materials were characterized by PL,Abs,TEM,XRD,Eg and so on.The analysis shows that CH₃NH₃PbBr₃ nanocrystalline with smaller size can be prepared by using oleylamine as capping molecule,and the quantum yield is able to reach about 70%.