Controllable Synthesis Of Inorganic Lead Halogen Perovskite And Modification Of Europium Ion Doping

Recently,all-inorganic halide perovskite nanomaterials(CsPbX3,X=I,Br,Cl)due to their high photoluminescence quantum yield,carrier mobility,high and narrow emission spectrum intensity,covering the entire visible light range(400-700 nm)and other excellent optical properties have attractive application potential in the field of display lighting.However,CsPbX3 has strong ionicity,which leads to poor internal structure stability,and is susceptible to factors such as light,temperature,and moisture At the same time,lead ions are toxic,which have caused their widespread application problems.Some researchers focus on improving the efficiency of perovskite-related devices,and in fact the modification of the material itself is also critical.There have been many reports on synthetic methods for CsPbX3 NC,but there is a lack of in-depth research on the kinetics of material growth.At the same time,the results of synthesizing CsPbX3 NC with good luminous efficiency,high stability,high yield and low toxicity were not significant.Therefore,exploring the simple and controllable synthesis of CsPbX3 NC and enhancing the stability and tunability of CsPbX3 NC is very important to break through its application bottleneckThe work in this thesis starts with two synthetic methods,hot injection and room temperature saturation recrystallization.The morphology control,synthesis mechanism and stability improvement of CsPbX3 NC are studied.The main research contents are as follows1.CsPbX3(X=Cl,Br,I)was prepared by hot injection method,and the effects of reaction temperature and reaction time after hot injection on the morphology and luminescence properties of perovskite NCs were systematically studied.The results show that by adjusting the reaction temperature and the reaction time after thermal injection,the synthesized CsPbBr3 NC has a fluorescent luminous efficiency(PLQY)of 99.8%and achieves narrow-band emission(FWHM<20 nm).Based on this,it is revealed that there is a focused and defocused growth process of perovskite nanocrystals in the corresponding temperature range.Finally,WLED was successfully prepared using CsPbBr3 NC as a green emitter.The device has a color gamut of 123%of NTSC and has excellent display characteristics2.The Eu3+doped CsPbBr3-Cs4PbBr6 green light-emitting perovskite solid powder was synthesized by a saturated recrystallization method at room temperature,which enhanced the solid-state light-emitting intensity and stability of CsPbBr3-Cs4PbBr6 and the powder yield was as high as 80%.The material exhibits red and green light emission at low temperature,which can be attributed to the energy transfer of Eu3+.By analyzing the doping mechanism,it is found that the surface state defects of the passivation of europium ions and the enhancement of energy transfer in the corresponding band structure make the quantum efficiency of the perovskite solid fluorescent powder increase to 87%.Finally,compared with CsPbBr3-Cs4PbBr6,the doped composite exhibits good water stability.After mixing it with AB glue,it can maintain 60%of the initial luminous intensity after soaking in water for 1 month.