Study On Preparation And Mn Ion Doping Of CsPbBr₃ Perovskite Nanocrystals

Metal halide perovskite has received widespread attention as a luminescent material promising for the next generation of high-quality lighting and high-definition displays.It has excellent optical performance and directly adjustable band gap,strong light absorption coefficient,high defect tolerance rate and low non-radiative recombination rate,which is extremely attractive to modern optoelectronic devices.However,due to the defects of the solubility and ionic diversity of the metal halide perovskite precursor solution,and the instability of the metal halide perovskite in a polar environment,its preparation and application are limited.Aiming at the shortcomings of the existing metal halide perovskite nanocrystals,this paper proposes the preparation of high-performance CsPbBr₃nanocrystal colloidal solutions and films based on organic amines as ligands to reduce the defects caused by solvents.CsPbBr₃nanocrystals were prepared in a polar environment with ethanol and doped with Mn ions to improve the stability and optical properties of CsPbBr₃nanocrystals.The main research contents are as follows:(1)Alkylamine assists the preparation of CsPbBr₃perovskite colloidal solution.The ligand-assisted reprecipitation method was used to prepare the optimal alkylamine ligand concentration to be 15 m M.The results showed that the alkylamine as the ligand is mainly due to the interaction between N and Pb,and octylamine is better than butylamine.The CsPbBr₃perovskite colloidal solution prepared by the ligand has better optical properties and stability,and the luminescence quantum yield(PLQY)is 54.3%.(2)Organic amine assists the preparation of high-performance CsPbBr₃perovskite nanocrystalline film.Further explore the preparation of CsPbBr₃nanocrystalline film with organic amines,and determine the optimal ratio of the respective ligands to the precursors.It shows that organic amines as ligands are mainly based on the interaction between N and Pb and Br.The AP-CsPbBr₃nanocrystalline film has excellent optical properties and stability,and its PLQY=55.7%.This provides the possibility for the application of CsPbBr₃perovskite nanocrystalline film in the future light-emitting device applications.(3)Synthesis and characterization of CsPbBr₃nanocrystals in a polar environment.A method of preparing CsPbBr₃nanocrystals under the polar environment of water and ethanol was proposed,and the experimental conditions such as solvent volume ratio,ligand concentration,and Cs/Pb ratio were optimized.The results showed that PLQY=22.68%,dispersed in a solution of V ethanol:V water=10:1,its fluorescence intensity maintained its original 50%within 4 h.The difference between?-CD and ethanol obtained by the proton nuclear magnetic resonance spectrum was determined by6H and-OH form a hydrogen bond to interact with each other.(4)Mn ion exchange doping of CsPbBr₃nanocrystals in a polar environment.It is determined that 20 mol%doping of Mn ions improves the stability and optical properties of CsPbBr₃nanocrystals.The results showed that PLQY=25.65%,dispersed in a solution of V ethanol:V water=10:1,the fluorescence intensity remained at 64%within 4 h.Through a series of physical characterizations,it is preliminarily determined that Mn ions are doped into CsPbBr₃nanocrystals.Inductively coupled plasma atomic emission spectroscopy tests show that the actual doping amount of Mn ions is 1.5mol%.