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The photoluminescence properties of BiTaO4:Pr^3 and BiTaO4 at room temperature were studied, and the infrared transmission and diffusion reflection spectra of BiTaO4 were measured. The photoluminescence spectrum of BiTaO4 peaks at about 420, 440 and 465nm. There has an obvious excitation band from 330 to 370nm. The photoluminescence spectrum of BiTaO4:Pr^3 consists of the characteristic emission of Pr^3 , and its main peak is at 606 nm from ^3P0→^3H6 transition of Pr^3 . Its excitation spectrum consists of the wide band with maximum at 325nm, the wide band in the range of 375-430nm, and the characteristic excitation of Pr^3 .The bands at 325nm and 375-430nm may be from the absorption of the charge transfer transition of the tantalate group and defect energy levels in its forbidden band, respectively.There is energy transfer from host to Pr^3 . Because both the host density and photoluminescence peak intensity of BiTaO4:Pr^3 are superior to PbWO4, BiTaO4:Pr^3 may be a potential heavy scintillator. 相似文献
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The photoluminescence properties of BiTaO4∶Pr3+ and BiTaO4 at room temperature were studied, and the infrared transmission and diffusion reflection spectra of BiTaO4 were measured. The photoluminescence spectrum of BiTaO4 peaks at about 420, 440 and 465 nm. There has an obvious excitation band from 330 to 370 nm. The photoluminescence spectrum of BiTaO4∶Pr3+ consists of the characteristic emission of Pr3+, and its main peak is at 606 nm from 3P0→3H6 transition of Pr3+. Its excitation spectrum consists of the wide band with maximum at 325 nm, the wide band in the range of 375~430 nm, and the characteristic excitation of Pr3+. The bands at 325 nm and 375~430 nm may be from the absorption of the charge transfer transition of the tantalate group and defect energy levels in its forbidden band, respectively. There is energy transfer from host to Pr3+. Because both the host density and photoluminescence peak intensity of BiTaO4∶Pr3+ are superior to PbWO4, BiTaO4∶Pr3+ may be a potential heavy scintillator. 相似文献
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纳米ZnO的研究及其进展 总被引:35,自引:0,他引:35
纳米ZnO的许多优异性能使其成为人们研究的热点并得到广泛的应用。随着ZnO颗粒尺度的不断减小,其量子限域效应越来越明显,观察到电荷载流子,声子,光子的局域化效应;表面、界面态对其性质影响逐渐明显,通过表面修饰和置入多孔及束管等束缚结构,可有效增强ZnO紫外(一个量级)或可见光区(1-2个量级)的发射强度;并使ZnO的电导率,磁化率有很大提高,纳米ZnO与其他材料的复合体系能得到一些新的功能材料。纳米ZnO的自组织行为,使人们可以获得许多形态各异,特殊用途的纳米材料及器件。本文综述了近年来纳米ZnO的研究新动态。 相似文献
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首次报道了用不同浓度的Al离子注入于蓝宝石衬底上的GaN薄膜(注入能量为500keV、注入浓度为10^14-10^15cm^-2),在做了不同温度和不同时间的快速热退火处理以及常规热退火处理后,在12K下用He-Cd激光(325nm)激发得到其发射谱。结果显示,经大剂量Al注入后的样品,其光致发光谱中3.45eV的带边激子发光以及2.9-3.3eV的4个声子伴随峰消失,此表明大剂量Al注入对GaN的晶体结构造成严重的损伤,以致本征发光消失。经10^14cm^-2剂量Al注入后的样品,在N2气氛中退火处理后,2.2eV缺陷发光峰得到了一定程度的恢复。而且,经常规退火处理后,此发射峰比快速退火处理的样品发射峰恢复得更好(其积分光强高3倍)。相似的结果亦显示于10^15cm^-2浓度的Al注入的样品。2.2eV黄色荧光源于GaN的缺陷(如Ga空位VGa),或VGa-H2,或VGa-ON复合体),其能级位于价带顶以上约1.1eV处。荧光发射可以来自“导带-缺陷能级”的跃迁,也可能来自浅施主(如N位O,能有位于导带下-10meV)至上述缺陷能级之间的跃迁。I-V测量显示,Al的注入区成为-10^12Ω.cm^-1高阻膜,这表明Al的注入可能产生了某种深的电子陷阱,由于电子陷阱可俘获导带电子,导致发光猝灭,而退火可使与黄色荧光相关的缺陷得到部分恢复,因而2.2eV发射峰有所恢复。 相似文献
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As an improvement of reported Y2O2S:Tb^3+, a white-light long-lasting phosphor: Y2O2S:Tb^3+, Sm^3+ was prepared by the solid-state reaction. The photo-luminescence spectra showed that the position and shape of Tb^3+ and Sm^3+ emissions under UV excitation were similar in this host, which ensured a stable white emission color (daylight standard of IEC) under different excitations. The decay curves of co-doped samples indicated that the decay times of emissions of the two ions were close. The thermo-luminescence measurement suggested that the traps created by the doped Sm^3+ ions were helpful to postpone the white afterglow of co-doped samples. Therefore, the function of co-doped Sm^3+ ions was confirmed as improving the white emission colors of samples and acting as new trap centers. 相似文献
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The luminescent properties of PbW04: Gd3 were studied. The luminescence of Gd3 in PbWO4: Gd3 was quenched. It is possible that the excitation states of Gd3 locate in the conduction band of PbW04 crystal. The luminescent intensity of the green and the blue band of PbW04 emission increases by doping with about 0.005% and 0.01% (molar fraction) Gd3 respectively. Mechanism of this enhancement of PbWO4:Gd3 luminescence is probably due to energy transfer from Gd3 to PbW04 host in the crystal. The PbW04 doped with low concentration of Gd (about 0.005% -0.01% ) is a good scintillating material. 相似文献
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高密度发光材料γ-Bi2WO6:Pr3+的发光性质研究 总被引:6,自引:0,他引:6
研究了用固相法制备的高密度发光材料γ-Bi2WO6Pr3+的结构、光致发光光谱、激发谱和γ-Bi2WO6的漫反射谱.由实验测得它的晶格参数为a=5.45A,b=16.42A,c=5.43A,密度Dx=9.53g/cm3.它的光致发光光谱主发射峰位于600、608、611、629nm,分别来自于pr3+的1D2→3H4、3P0→3H5、3P0→3H6、3P0→3F2跃迁的发射.其激发谱由位于约225~430nm范围内、最大值约在372nm的主激发带和450nm的激发峰组成;主激发带来自于基质,可能是基质的带间吸收、W-O间电荷迁移吸收和缺陷能级的吸收;450nm的激发峰来自于pr3+的3H4→3P2跃迁吸收.BWOPr3+的最佳掺杂浓度为0.8mol%左右. 相似文献