Synthesis And Properties Of Cesium Lead Halide Perovskite Nanocrystals Composites

In recent years,lead halide perovskite has been used in solar cells,light emitting diodes,lasers and other fields due to its excellent photoelectric properties.At present,how to combine perovskite with other materials to design and synthesize perovskite composite materials with better structure and better performance has become a research hotspot.Therefore,in this thesis,the corresponding perovskite composites were prepared by combining lead halide cesium perovskite nanocrystals with silver nanorods and mesoporous molecular sieves,and their unique optical properties were studied in depth.In the first chapter of this thesis,we gave a brief overview of the field of halide perovskites,including the structure,properties and synthesis methods of halide perovskites.In addition,we also briefly introduced chiral and chiral perovskite materials,including their development,properties,and applications.In the second chapter of this paper,we prepared chiral nematic liquid crystalline phase of Ag nanorods@silica@cysteine@quantum dots hybrid nanorods composite structure by coating silver nanorods with silica,cysteine,and all-inorganic perovskite quantum dots.It was found that the chiral signal was derived from the interband absorption-enhanced optical activity of structural arrangement of cysteine molecules,the chiral nematic liquid crystalline arrangement of the Ag nanorods,and the exciton adsorption edge of the perovskite.Due to the local surface plasmon resonance field enhancement effect of silver,the luminous intensity of perovskite quantum dots can be increased by 87 times.In addition,we use this material to prepare high-performance green light-emitting diodes.In the third chapter of this paper,we used mesoporous molecular sieve MCM-41as the template and prepared Mn²⁺-doped all-inorganic perovskite nanocrystals by using template-assisted synthesis strategy.Due to the quantum confinement effect of MCM-41,CsPbBr₃ nanocrystals can be made a large luminescent blue shift,and the doping of Mn²⁺can adjust the formation energy of CsPbBr₃ nanocrystals,thereby controlling the coprecipitation of bulk materials.In addition,the presence of mesoporous molecular sieves greatly enhanced the ultraviolet and air stability of the perovskite nanocrystals.We used them as phosphors for solid-state lighting and prepared white light-emitting diodes.