Study On The CH₃NH₃Pb（Mn/Eu/Cu/Sn）X₃（X=Cl,br,I） Total Chromatographic Quantum Dots With Synthesis,Stability And Its Fluorescence Property

Owing to the excellent optoelectronic properties of organic-inorganic hybrid perovskite QDs（such as narrow half-peakwidth,high quantum efficiency and energy band tunability,etc.）,it has a broad market prospect in the field of photoelectricity and photocatalysis.Using room temperature crystallization method to synthesize quantum dots has the advantages of simple operation and low energy consumption.However,the uncontrolled-morphology,lead toxicity and low stability of quantum dots have been restricting their application in the field of photoelectricity.In this paper,the organic-inorganic hybrid perovskite QDs with controllable morphology,low toxicity and high stability were synthesized.The details are as follows:（1）A series of MAPbX₃（MA=CH₃NH₃⁺,X=Cl,Br,I）perovskite QDs were synthesized via room temperature crystallization method by adjusting the proportion of halogens,which achieve full-chromatographic emission in the visible range.On this basis,the nanosphere,nanorod and nanosheet morphologies of MAPbBr₃ perovskite quantum dots have been obtained by changing the ligand type as well as the ligand proportion.With the change of morphology,the fluorescence emission peak red shifted and the fluorescence lifetime increased gradually.The influence mechanism was systematically studied.（2）In the light of lead toxicity,on the one hand,using the non-toxic Mn²⁺and Eu³⁺partial substitution of Pb²⁺,the reduction of the toxicity of MAPbCl₃ perovskite QDs was achieved.Meanwhile,with the energy transfer from the MAPbCl₃ matrix to Mn²⁺and Eu³⁺,the luminous colors of MAPb（Mn/Eu）Cl₃ perovskite QDs were changed from blue to orange-red and cyan transformations,respectively.The mechanism of energy transfer on the properties of MAPb（Mn/Eu）Cl₃ perovskite QDs was systematically investigated.On the other hand,the use of the non-toxic Cu²⁺and Sn²⁺to replace Pb²⁺not only reduced the toxicity of MAPb（Cu/Sn）Br₃ QDs,but also fine-tuning their luminous color due to the band gap of the quantum dots changed.The influence mechanism was systematically studied.In view of the shortcomings of quantum dot stability,the surface of the quantum dots was modified by SiO₂,which obtained the organic-inorganic hybrid perovskite QDs with high stability and water solubility.The fluorescence properties of the quantum dots were analyzed to obtain more stable quantum dots.