| Alkaline-earth metal titanate is a good luminescent materials matrix for its excellent chemical stability and the appropriate band gap. Especially, the phosphor of Ca2Zn4Ti16O38:Pr (shorted:CZT:Pr) exhibits persistent red emitting by visible light excitation and its excitation spectra extend from ultraviolet light to visible light (250-500 nm). The excellent thermal stability and strength characteristics of CZT:Pr made it a good candidate to be studied for novel optical ceramic materials. It has been reported that the traditional solid-state reaction for preparing CZT:Pr requires for 96 h and t sol-gel method to prepare this phosphors needs for 21 hat 950℃.These drawbacks of synthesis approaches are not consistent with today's advocates of green energy-saving preparation methods. Therefore, optimization of synthesis conditions of CZT must be carried out.Besides, the weak luminescence and short afterglow decay properties are the shortcomings of phosphors. So, by co-doping rare-earth ions to find the auxiliary activator to improve the luminescence and afterglow properties, is also a key research paper one of the elements.This paper has been also studied a single-doped Eu3+, Sm3+ions in titanate phosphor in order to achieve the CZT as a substrate to effectively absorb the blue and green light in sunlight. The specific contents are as follows:1. Controllable synthesis and properties of Ca2Zn4Ti16O38:Pr crystallineBy changing the raw materials, we have studied the different pH value of precursor solution on the component, morphology and photoluminescence of CZT:Pr phosphor by sol-gel method. The XRD and SEM results showed that uniform particles small, spherical, phase single CZT:Pr phosphor at 900℃calcined 8 h in the high-temperature furnace when pH≤3; Excitation and emission spectra indicate that the phosphors exhibit the highest excitation bands in the visible region from 450-495 nm, as well as red emitting of Pr3+at 614 nm(1D2→3H4)and 644 nm (3P0→3F2) when pH≤3.Preparation conditions are as above the same precursor structure, a single phase of CZT:Pr obtained at 800℃calcined 2 h by microwave while a better luminescence and afterglow of phosphor obtained at 900℃,4 h. CZT:Pr phosphor not only kept its excellent luminescence and afterglow properties but also reduced reaction temperature and shortened the reaction time by Sol-gel-microwave method. This method is a kind of green energy-saving environment-friendly synthetic methods.2. Synthesis and luminescent properties of Ca2Zn4Ti16O38:Pr, REThe polycrystalline Pr3+and RE3+co-doped strontium aluminates CZT:Pr3+, RE3+was prepared by sol-gel reactions. The UV and visible-excited photoluminescence and persistent luminescence of the CZT:Pr3+, RE3+phosphors with different composition and doping ions were studied and compared. The results showed that different co-doping RE3+ions showed a different effect on persistent luminescence. Only the Lu3+ion greatly improved the persistent luminescence of CZT:Pr3+while Ce3+, Nd3+, Tb3+ions can hardly improve the luminescence. The doped Eu3+and Sm3+ions in CZT:Pr3+phosphors work as the luminescent center, the characteristics of Pr3+luminescence disappeared. 3. Synthesis, characterization and luminescent properties of novel Ca2Zn4Ti16O38:RE (RE=Eu3+, Sm3+) phosphorsA novel red CZT:Eu3+and an orange-red CZT:Sm3+phosphor prepared by sol-gel method, in which the Eu3+, Sm3+ions as activators, respectively. The XRD showed that Eu3+, Sm3+doped did not change the structure and composition of the matrix. Excitation and emission spectra indicated that the phosphor CZT:Eu3+could adsorb the near-ultraviolet, blue and green to convert red or orange-red light, and show a certain degree of long-lasting performance.CZT:Eu were prepared in appropriate amount of C powder more effectively absorb the blue-green light to convert into 616 nm long-lasting red emission than in the air condition.
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