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Spectroscopic properties and mechanism of Tm^3+/Er^3+/Yb^3+ co-doped oxyfluorogermanate glass ceramics containing BaF2 nanocrystals 下载免费PDF全文
Transparent Tm^3+/Er^3+/yb^3+ co-doped oxyfluorogermanate glass ceramics containing BaF2 nanocrystals are prepared. Under excitation of a 980-nm laser diode (LD), compared with the glass before heat treatment, the Tm^3+/Er^3+/yb^3+ co-doped oxyfluorogermanate glass ceramics can emit intense blue, green and red up-conversion luminescence and Stark- split peaks; X-ray diffraction (XRD) and transmission electron microscope (TEM) results show that BaF2 nanocrystals with an average diameter of 20 nm are precipitated from the glass matrix. Stark splitting of the up-conversion luminescence peaks in the glass ceramics indicates that Tm^3+, Er^3+ and (or) Yb^3+ ions are incorporated into the BaF2 nanocrystals. The up-conversion luminescence intensities of Tm^3+, Er^3+ and the splitting degree of luminescence peaks in the glass ceramics increase significantly with the increase of heat treat temperature and heat treat time extension. In addition, the possible energy transfer process between rare earth ions and the up-conversion luminescence mechanism are also proposed. 相似文献
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以甲基磺酸和碳酸镉为原料,采用普通溶液法制备甲基磺酸镉(Ⅱ),其产物为白色结晶固体。采用红外、核磁、热重、扫描电镜和X射线单晶衍射多种方法对化合物进行表征。结果表明:甲基磺酸镉含有两个结晶水,热稳定性好,属于三斜晶系,■空间群;晶胞参数a=0.4785(5)nm,b=0.6101(5)nm,c=0.8232(5)nm,α=87.137(5)°,β=84.461(5)°,γ=85.614(5)°,V=0.2383(3)nm~3,Z=1。以N1-甲基3,4-二氢嘧啶酮的合成为探针反应,考察了甲基磺酸镉对Biginelli反应的催化性能。在无溶剂、绿色条件下,产品收率达90.1%,重复使用三次后。产品收率仍可以达到80.3%。最后,对甲基磺酸镉连续催化后,催化活性略有下降的原因进行了分析。 相似文献
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高温固相法制备了Yb3+/Tm3+共掺的Sb2O4发光粉体,研究了其上转换发光性质。在980nm半导体激光器的激发下,样品发射较强的近红外(800nm)和较弱的蓝色(480nm)及红色(680nm)上转换发光。粉末样品中稀土Yb3+及Tm3+浓度对上转换发光性质具有显著的影响,随着Yb3+或Tm3+浓度的增加,上转换发光增强;Tm3+掺杂浓度达0.8%时其上转换发光强度达到最大,之后上转换发光随Tm3+浓度的增加而减弱,这是由于浓度猝灭引起的。探讨了粉末样品的上转换发光机理,在980nm激发下Tm3+的蓝光和近红外上转换发光均属于二光子的上转换发光过程。 相似文献
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Bismuth (Bi)-doped materials have attracted a great deal of attention because of their broadband nearinfrared (near-IR) emission around the wavelength utilized in telecommunications. In this study, broad near-IR emission band from 1 100 to 1 650 nm is generated in the Bi-doped 90GeS2-10Ga2S3 glass and glass-ceramics under 820 nm of light excitation. Based on the analysis of the absorption and emission spectra, the origin of this broadband emission is ascribed to the Bi2-2 dimers. The precipitation of β-GeS2 nanocrystals drastically enhances the emission intensity and lifetime of Bi-doped chalcogenide glass. 相似文献