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Synthesis And Photoluminescence Characteristics Of The Full-color Phosphorescent Material

Posted on:2011-12-07Degree:MasterType:Thesis
Country:ChinaCandidate:L YangFull Text:PDF
GTID:2121330332463742Subject:Materials Physics and Chemistry
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Light-storing material also known as long afterglow luminescent material, is capable of absorbing sunlight or ultraviolet ray during the day, storing energy of light and releasing the energy in the form of visible light when the light is stopped. At present, blue and green long afterglow materials have been developed maturely. Compared with the above two kinds of color's material performance, on its illumination brightness and the after time the red long afterglow material has the big disparity, therefore, the development of red afterglow material with good performance, has important theoretical significance and practical value.A new idea of preparation of red long afterglow material is to be adopted in this subject. The blue, green long afterglow materials with excellent performance were used as the excitation light source and their afterglow constantly excites the red fluorescent material and has it release red light. Then the red long afterglow materials can be indirectly gotten.In this paper, we select a kind of organic dyes Rhodamine B and two kinds of inorganic materials Sr3Al2O6:Eu3+ and manganese-activated magnesium fluorogermanate which were synthesized by high-temperature solid-state method as the red fluorescent materials, study their luminescence performance and their optimal preparation route.The good performance of violet (PLP-6),blue (PLB-8B) or yellow green(PLO-8B) long afterglow materials are mixed with the red fluorescent materials, and then the properties of the composite materials can be researched.PMMA, which is colorless, transparent and has good optical properties, is prepared by radical polymerization and used as the mixed samples' carriers. Rhodamine B's luminescence properties are influenced by its chemical environment strongly. In PMMA, it can be easy motivated by the yellow green light of which peak is at 555nm, and emits the orange ray whoes peak is at 580nm.Rhodamine B(R) is mixed with PLO-8B(G) according to different mass ratio.A lamp is used to irradiate the mixed samples.When the power is shut, the red afterglow can be observed obviously. The composite light color is varied according to different mass ratio.Red fluorescent material Sr3Al2O6:Eu3+ which can be excited by visible light is synthesized by high temperature solid-state method. Upon excitation with 392 nm and 462 nm light, the sample exhibits narrow emission peaks due to the 5DJ(J=0,1,2,3)to 7FJ(J=0,1,2,3,4,5) transitions of Eu3+ ion. The main emission peak is constituted by two peaks at 612nm and 617nm which are ascribed to the hypersensitive forced electric-dipole 5D0 to 7F2 transition. The afterglow effect of sample itself is not obvious.When PLP-6 or PLB-8B is mixed with Sr3Al2O6:Eu3+, the mixed samples' afterglow properties can be improved. The initial intensity of the afterglow is strengthened, and the duration time is prolonged.Red fluorescent material manganese-activated magnesium fluorogermanate(S) is synthesized by high temperature solid-state method. The excitation band extends from 280nm to 440nm, so it can be excited by blue-violet light in the visible region. The sample exhibits five sharp emission peaks due to the 2E→4A2 transitions of Mn4+ ion. The main emission peak is at 657nm. Sample itself almost does not have the ability to emit afterglow. When PLP-6(V) or PLB-8B(B) is mixed with S,the mixed samples can perform good afterglow properties.In the graph of the long afterglow decay curves, the significant difference of phosphorescent intensity between the mixed sample and the pure afterglow material, and the distinct red afterglow peak in the long afterglow spectra, both confirm the design of this subject. Mixing S and V according to different mass ratio,the different color afterglow can be obtained. With the proportion of S increasing, the mixed samples'color tends to purple.When the mass ratio S:V is 9:1,the sample's afterglow property is ideal, and its color coordinate is (0.2302,0.0492)in CIE1931 chromaticity diagram.
Keywords/Search Tags:red long afterglow, high temperature solid-state method, visible light excitation, Rhodamine B, Sr3Al2O6:Eu3+, manganese-activated magnesium fluorogermanate
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