【摘要】 本文用蒸发溶液法生长了一系列CeP₅O₁₄:Mn晶体,测定了它们的组成和结构。测定了晶体的吸收光谱,激发光谱和发射光谱,观察到Ce³⁺→Mn²⁺之间的能量转移和在此体系中锰离子在545nm附近和665nm附近两个波段同时进行发射,并随着锰含量的增加,665nm的荧光强度下降而545nm的强度增加。更多还原

【Abstract】 Cerium pentaphosphate,CeP5O14,is an ultrafast scintillator,which has a uv-emission band with an extremely short lifetime (about r1 = 12nsec.).Ce3 + in cerium pentaphosphate has a broad uv-absorption band.So it can be used as sensitization ion. We have investigated a new crystalline luminescence material, CeP5O14:Mn, which can emit strong green-yellow light.A series of CeP5O14:Mn crystals were grown from phosphoric acid by the evaporation solution method. The usual experimental conditions are as follows:The manganese carbonate (purity:A.R.) is added to a gold crucible, in which G.R.-grade commercial orthophosphoric acid, H3PO4, containing 15% by weight of water, is filled. As the manganese carbonate has been dissolved completly, the cerium oxide (purity:99.99%) is added into the solution.This mixture is heated in the crucible to about 250℃ and kept for about two days until the excess water has evaporated and the cerium oxide has dissolved. Subsequently the temperature is raised to about 550℃. After a week the crucible is taken out and the mother liquor is poured out of the crucible. The crystals are rinsed in hot water repeatedly. The CeP5O14:Mn crystals, colourless or with a pale yellow colour could be obtained.CeP5O14:Mn crystal compositions were determined by chemical analysis. No obvious change in Ce% content was observed when Mn% content was small. The structure of CeP5O14:Mn crystal was determined.When the content of Mn% in the crystal was low, the crystal structure of CeP5O14:Mn was the same as that of CeP5O14, both belong to the monoclinic system, space group P21/c. Some lattice parameters of CeP5O14 :Mn were calculated by a computer. The results are shown in table 1.The CeP5O14:Mn crystals emit strong green-yellow light when they were excited by 254nm ultraviolet light.The luminescence intensity increases with the increase of Mn% content. CeP5O14 emits ultraviolet light and no luminescence of LaP5O14 :Mn was observed.The results indicate the energy transfer from Ce3+ to Mn2 + exists.The absorption spectra show that CeP5O14 has a strong absorption peak in the wavelength range of 255-320nm, LaP5O14:Mn has a weak peak at 290nm, and when CeP5O14 is doped with manganese, the absorption peaks move toward the shorter wavelength side and a split of absorption peak were observed (fig.1).The excitation spectra of CeP5O14:Mn has been measured. The excitation peak of CeP5O14:Mn is the same as that of CeP5O14. The intensity of the strongest peak shown at 302nm decreases as the content of Mn% increases.The emission spectra of CeP5O14:Mn under excitation of 302nm show three groups of emission peaks at about 332, 545, and 665nm. But CeP5O14 has only one group peaking at about 332nm, so the other two groups peaking at 545 and 665nm are considered as emission of manganese ion.An interesting phenomenon was observed, as the content of Mn% was increased, the emission intensity at 545nm was increased, while that at 685nm was decreased. As shown in fig,4 and fig,5,更多还原