| In recent years,anew type of luminous material,organic-inorganic hybrid halogen perovskite,has been paid more and more attention by scholars in the field of optoelectronics because of its excellent performance in perovskite solar cells.This material also has good luminous properties in the field of display.Through the regulation of halogen ions,the full coverage of the lumnous range in the visible light region can be realized,which is of far-reaching significance to the development of LED.However,organic-inorganic perovskite contains organic amines,which is very sensitive to light,heat and water environment because of its poor stability,which greatly limits its application in devices.The preparation of all-inorganic perovskite with inorganic ions instead of organic amines can greatly improve the stability of the materials.The stability of all-inorganic perovskite material CsPbX3(X=Cl,Br,I)is much better than that of organic-inorganic hybrid perovskite,and it has superior optical properties.Therefore,it is of great significance to explore the preparation of all-inorganic perovskite material CsPbX3(X=Cl,Br,I)and the application of optoelectronic devices to the development and commercialization of LED lighting technology.In this paper,the preparation method of all inorganic perovskite Cs-Pb-X(X=Cl,Br,I)system is studied,and the materials are prepared by room temperature supersaturation crystallization method,anion exchange method and one-step method,and the advantages and disadvantages of the three methods are compared to find out the best preparation conditions.In addition,orange fluorescent materials are successfully prepared by doping Mn2+ into CsPbCI3,and green and white LEDs are prepared with CsPbBr3 and CsPbClxBr3-x as luminous layers.Finally,the preparation and properties of three kinds of perovskite,such as CsPb2Br5,Cs4PbBr6 and Cs3Cu2I5 are discussed.The main contents are as follows:(1)The diffraction peaks of CsPbCl3,CsPbBr3,CsPbI3 of three perovskite materials prepared by room temperature supersaturation crystallization method correspond to the cubic phase,monoclinic phase and orthogonal phase of the standard card PDF#73-0692,PDF#18-0364,PDF#18-0376,at room temperature,respectively.The luminous regions were blue,green and red,respectively.(2)CsPbCl3:Mn2+orange phosphor was successfully prepared by doping CsPbC13 with Mn ion,and the phase and structure of CsPbC3:Mn2+orange phosphor were not changed by doping.The absorption peak and luminous peak of the phosphor were at 373,594nm,respectively.When the molar ratio of doping concentration was Pb:Mn=1:2;the luminous intensity was the strongest.Using CsPbBr3 and CsPbClxBr3-x as luminous layer and LED ultraviolet chip,green and warm white LED,were successfully synthesized.The main wavelength of green LED is 525.6 nm,the color purity is 94.2%,and the luminous intensity is high.The color coordinate of warm white LED is(0.3865,0.3274),which is close to the standard white light,the color temperature is 3354K,which meets the requirements of warm white light,and both green and warm white LED can be commercialized.(3)Three perovskite-like CsPb2Br5,Cs4PbBr6 and Cs3Cu2I5 were successfully prepared by supersaturation crystallization method,and their diffraction peaks correspond to the diffraction peaks of standard card PDF#25-0211,PDF#73-2478 and PDF#45-0077,respectively.At room temperature,the crystal structure is tetrahedral phase,hexagonal phase and orthogonal phase,respectively.CsPb2Br5 has no fluorescence properties,but Cs4PbBr6 has superior optical properties,and the luminous region is located in the green light region.Cs3Cu2I5 has certain fluorescence properties.The absorption peak and the luminous peak are located at 3 02,434nm,and the luminous region is located in the blue light region. |
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