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The nature of the emission center of Eu~(2 ) in KCaF_3:Eu~(2 ) strongly depends on the preparative condi-tions.Experimental results show that there are two different d→f transition emission bands,and the origin ofthese two emission bands,their interrelationship and the effect of doping concentration on them have been dis-cussed.A Eu~(2 )-Eu~(3 ) valency change process has been proposed. 相似文献
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输出0.9μ激光的砷化镓半导体激光器是一小型简易,价格便宜的激光器,它已在军用上和医疗上得到应用。收到了较好的效果。但是0.9μ激光是在红外波段,人眼看不到,这给激光的操作和使用带来了困难,近红外光的探测和显示可应用红外变相管来实现,可它的价格较贵,又需一定大小的装置,使用很不方便,且需上万伏的高压 相似文献
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本文采用固相反应法合成了一系列掺Ce ̄(3+)、Tb ̄(3+)的四硼酸铝钇(Y_(1-x-y)Ce_xTb_yAl(BO_3)_4)磷光体。测定了它们的结构、属于三方晶系、空间群R_(32)、Ln ̄(3+)离子处于六个氧形成的三棱柱中。测定了磷光体中Ce ̄(3+)、Tb ̄(3+)和Ce ̄(3+)-Tb ̄(3+)共掺时的光谱,观察到Ce ̄(3+)、的Stokes位移相当小(~1700cm ̄(-1))、Tb ̄(3+)的能级劈裂较明显和Ce ̄(3+)能将能量传递给Tb ̄(3+),测定了磷光体中Ce ̄(3+)、的荧光寿命,探讨了Ce ̄(3+)-Ce ̄(3+)之间的能量传递。 相似文献
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Eu~(2+)激活的钡镁多铝酸盐磷光体的合成 总被引:1,自引:0,他引:1
本文试验了合成BaMg_2Al_(16)O_(27):Eu~(2+)的一些主要因素如灼烧温度,一些化学组分改变的影响。试验表明,提高灼烧温度有利于产物发光,但灼烧温度高于1340℃发光亮度不再增加,合适的Eu~(2+)掺入浓度在0·12~0·18克原子范围。Mg~(2+)量和配方中F量的不同对发光亮度、萤光光谱、色纯度和粒度均有影响,通过试验得到了较适宜的BaMg_2Al_(16)O_(27):Eu~(2+)磷光体的制备条件。 相似文献
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In this paper,the influence of crystal-field on the Luminescence properties of Eu~(2 ) in complex oxidesare studied theoretically by using purely electrostatic model,the dependence of the 4f~65d levels on Eu-Obond distance is given.Quantum chemistry calculation shows that the splitting extent of 4f~65d energy band incubic or in octahedral fields will be inversely proportional to R~5,where R is the distance of Eu~(2 ) to oxygenligand.The value of R affects slightly the location of the centre of 4f~65d energy band.According to the exper-imental spectrum data,we have discussed the influence of the host chemical composition,the replaced sites ofEu~(2 ) and degree of covalency of Eu-O bond on luminescence properties of Eu~(2 ).Some regularity offluorescence spectrum was observed.In alkali-alkaline earth-phosphates,the splitting extent of 4f~65d band (△E) becomes smaller as theEu-O bond distance (R) increases.In Na_(3-x)(PO_4)_(1-x)(SO_4)_x and Na_(2-x)CaSi_(1-x)P_xO_4 hosts,d-d emissionpeak of Eu~(2 ) will shift to shorter wavelength with the increase of x's value.The crystal structure data show that Eu~(2 ) in K_2Mg_2(SO_4)_3 is affected more strongly by crystal-fieldand covalancy than in KMgF_3,so K_2Mg_2(SO_4)_3:Eu~(2 ) emits blue light (E_(em)~m=400nm) and KMgF_3:Eu~(2 )produces ultraviolet fluorescence. 相似文献
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