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《硅酸盐学报》2015,(11)
以碳酸氢铵为沉淀剂,采用共沉淀法制备了Er,Yb:(La Gd)2O3纳米粉体。经1 000℃煅烧2 h得到的粉体颗粒呈规则球形,平均粒径约为90 nm,团聚低,分布均匀。研究了Er3+,Yb3+的掺杂量对样品发光强度的影响。结果表明:掺杂Er3+和Yb3+的摩尔分数分别为4%和5%时,所得样品的发光性能最优。样品的激发和发射光谱显示:在379 nm处激发峰最强,对应Er3+的4I15/2→4G11/2能级跃迁;最强发射峰位于562 nm处,对应于4S3/2/2H11/2→4I15/2能级跃迁。样品的上转换光谱表明:样品在548和662 nm有较强的发射峰,对应Er3+的4S3/2/2H11/2→4I15/2跃迁和4F9/2→4I15/2跃迁。并讨论了发光跃迁机制。 相似文献
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采用高温固相法,通过引入添加剂Bi2O3制备了亚超细(约为500 nm)的上转换荧光粉Y2O2S:Er3+,Yb3+.采用X射线衍射、扫描电子显微镜、能谱、吸收光谱和荧光光谱研究了Bi2O3掺杂对Y2O2S:Er3+,Yb3+荧光粉晶体生长和和上转换发光特性的影响(在980 nm和1550nm波长下激发).结果表明:加入Bi2O3添加剂,由于低温烧结过程中产生液相影响晶体生长,制备出亚超细荧光粉.该荧光粉在980 nm和1550nm波长激发下发光强度有所降低,但仍产生较强上转换发光. 相似文献
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稀土文章采用水热法合成掺杂不同金属离子的Ti O2:Yb3+/Er3+上转换发光材料。系统的探讨了不同的金属离子对Ti O2:Yb3+/Er3+发光材料发光性能、形貌以及晶型的影响。具体到通过荧光光谱数据分析离子价态、离子半径等对红、绿光性能的影响;通过SEM数据分析掺杂不同金属离子对应样品形貌的变化;通过XRD数据分析掺杂不同金属离子对应样品的晶型的变化。结果表明离子价态以及离子半径都会改变Ti O2:Yb3+/Er3+材料的发光性能,但与Ti O2:Yb3+/Er3+材料发光性能之间不存在线性关系;掺杂不同金属离子不会改变样品的形貌;掺杂不同金属离子得到了纯相的Ti O2:Yb3+/Er3+样品,且不改变样品的晶型。 相似文献
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利用硫熔法制备了不同浓度的Yb和Ho掺杂的Y2O2S:Yb,Ho上转换发光材料。采用X线衍射仪、扫描电镜和荧光光谱仪对粉体的相组成、形貌和上转换发光性能进行表征。结果表明:不同浓度的Yb和Ho掺杂后没有改变Y2O2S的晶体结构;颗粒形貌较为规则,多呈现多面体状,分散性较好,颗粒表面很光滑;在980nm激光激发下,Y2O2S:Yb,Ho呈现出以绿光发射为主的上转换荧光,Yb的最佳掺杂量为8%(摩尔分数),Ho的最佳掺杂量为2%(摩尔分数),Ho3+和Yb3+掺杂浓度可显著影响不同颜色发射峰的强度;对激活离子Ho3+来说,同类离子之间发生能量传递和交叉弛豫行为,导致上转换荧光强度发生猝灭;对敏化离子Yb3+来说,Yb3+吸收能量,以热的形式释放出来,产生杂质猝灭。 相似文献
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采用高温固相法合成了白色长余辉发光材料Y2O2S∶Tb3+,Sr2+,Zr4+,利用X射线衍射、扫描电子显微镜、荧光分光光度计、照度计和热释光谱仪研究了煅烧温度对样品物相、形貌及发光性能的影响.结果表明:在950℃煅烧时,样品为Y2O3与Y2O2S的混合相,其中Y2O3为主相:在1000和1 050℃煅烧时为纯的Y2O2S相;当温度高于1 050℃时.再次出现Y2O3相;用288 nm波长光激发样品,Tb3+发射峰形状与位置不变,其中位于417nm蓝光与544nm黄绿光主发射峰归属于Tb3+的5D3→7F5与5D4→7F5跃迁;当煅烧温度为1 000℃时,样品的能级陷阱深度为0.64 eV,余辉时间为160s(≥1mcd/m2). 相似文献
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采用水溶液溶胶-凝胶法制备Ce2O2S、La2O2S干凝胶.合成的稀土硫氧化物可比高温固相法的灼烧温度降低,可大大节约能源,降低生产成本.并且所得到的产品为疏松多孔状,轻轻一压即可得到粉体.用X射线衍射仪作XRD图谱分析得样品硫氧化铈非晶体. 相似文献
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Yingjie Feng Xiangyang Liu Peng Zhang Yi Han Shuoyan Zhai Wei Pan Chunlei Wan 《Journal of the American Ceramic Society》2023,106(12):7736-7744
In this study, complex GdAlO3–Gd2Zr2O7 and high-entropy REAlO3–RE2Zr2O7 (RE = Nd, Sm, Gd, Eu, and Dy) composites with an equiaxed dendrite structure at eutectic composition are successfully fabricated using a gas levitation containerless solidification method. The unique microstructure of the composites is characterized, and the evolution process of the dendritic structure is explained. The formation of dendrites at eutectic composition is attributed to the rapid cooling induced by the shutoff of lasers and the homogeneous temperature field and nucleation achieved through gas levitation. The GdAlO3–Gd2Zr2O7 and high-entropy oxide composites exhibit enhanced fracture toughness compared to the bulk samples fabricated by solid-state sintering methods. The fracture toughness increases by 44% for GdAlO3–Gd2Zr2O7 bulk sample and 34% for high-entropy REAlO3–RE2Zr2O7 bulk sample, which can be attributed to the complicated interfaces introduced by the equiaxed dendritic microstructure and the high thermal mismatch stress between two phases. Additionally, the high-entropy REAlO3–RE2Zr2O7 oxides exhibit excellent high-temperature stability, with no significant change in dendritic microstructure or fracture toughness even after holding at 1573 K for 100 h. These findings suggest the potential of high-entropy eutectic oxide ceramics with dendrite microstructure for advanced engineering applications. 相似文献
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以高纯度的SrCO3、NH4VO3、Eu2O3和Yb2O3等为主要原料,采用高温固相法合成荧光粉。X-粉末衍射及荧光光谱证实合成了一种在可见光范围内有广泛吸收的发黄光的钒酸盐体系荧光粉。其中Eu3+的最佳掺杂摩尔浓度比为0.09,最佳煅烧温度为1223K。 相似文献
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报道了稀土离子Eu3+的含量对二维纳米发光材料[CdxMg6-xAl2(OH)16]2+[S2-@4H2O]2-发光强度的影响,并对基质中Cd2+离子的含量、硫化时间、灼烧温度等合成条件对发光材料发光强度的影响进行了研究. 相似文献
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The Sm3+-activated CaGd2(MoO4)4 phosphors were prepared through a sol-gel reaction route. From the results of excitation spectrum, three-dimensional emission spectra and contour lines, it was confirmed that the near-ultraviolet (NUV) light was the proper excitation light source for the synthesized phosphors. Under 405 nm irradiation, the luminescent behaviors of the studied samples were revealed to be dependent on the Sm3+ ion concentration and its optimal value of 0.03 mol was obtained. Through theoretical analysis, it is evident that the dipole-dipole interaction can be responsible for the involved concentration quenching mechanism in the final products and the critical distance was 39.7 Å. Moreover, the temperature-dependent emission spectra demonstrated that the studied samples had admirable thermal stability and the activation energy was decided to be 0.21 eV. Furthermore, the internal quantum efficiency of the Sm3+-activated CaGd2(MoO4)4 phosphors was found to be 21.6%. Finally, to explore the practical applications of obtained compounds for indoor illumination, a white light-emitting diode (WLED) device which contained a NUV chip, prepared phosphors, and commercial blue-emitting and green-emitting phosphors was packaged. The packaged WLEDs device can emit dazzling white light with satisfied color coordinate of (0.305, 0.318), proper color rendering index (82.6), and correlated color temperature (7069 K). 相似文献
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SO4^2-/TiO2-La2O3催化合成季戊四醇四乙酸酯 总被引:1,自引:0,他引:1
以稀土固体超强酸SO4^2-/TiO2-La2O3为催化剂,乙酸和季戊四醇为原料合成季戊四醇四乙酸酯,并考察了影响反应的因素。试验结果表明,SO4^2-/TiO2-La2O3对合成季戊四醇四乙酸酯具有良好的催化活性。其适宜反应条件为:催化剂用量占反应物质量的2.5%,且能重复使用性、酸醇摩尔比为8.00(醇为0.5 mol)、反应时间为90 min和带水剂甲苯为反应物总质量的28%,季戊四醇四乙酸酯的收率可达84%。 相似文献
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无毒透明稀土复合热稳定剂RHS—2的研制和应用 总被引:20,自引:1,他引:20
研究了硬脂酸稀土用作聚氯乙烯(PVC)热稳定剂的特性,研制出一种高效无毒稀土复合PVC热稳定剂RHS-2并进行了工业试用。结果表明:RHS-2特别适用于透明软PVC制品的加工,用RHS-2代替传统的有毒钡-镉或钡-镉-锌热稳定剂生产的制品无毒,透明性和力学性能均有所提高,且成本下降。 相似文献
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微波辐射稀土固体超强酸催化合成水杨酸-2-乙基己酯 总被引:6,自引:0,他引:6
以水杨酸和2 乙基己醇为原料,稀土固体超强酸SO2-4 La3+/TiO2为催化剂,在微波辐射下合成水杨酸 2 乙基己酯。考察了各因素对转化率的影响,优化条件为:微波辐射功率350W;反应时间3min;催化剂用量0 8g(对0 05mol水杨酸);n(水杨酸)∶n(2 乙基己醇)=1∶2.5;水杨酸转化率94 6%。 相似文献
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Jiangbo Wen Hongjie Wang Lei Fan Liting Wei Min Niu Hongfei Gao Zhixin Cai 《Journal of the American Ceramic Society》2019,102(1):136-143
Here we prepared porous silicon oxynitride (Si2N2O) ceramics by reaction sintering of SiO2 and Si3N4 using five different rare-earth oxides (RE2O3, RE = Lu, Yb, Y, Sm, and La) as sintering aids. The influences of RE2O3 on the formation, densification, microstructure, and mechanical properties of Si2N2O ceramics have been investigated in detail. The results have indicated that with the increase in RE ionic radius, the formation temperature of Si2N2O decreases, and the densification process could be promoted by RE2O3 with larger RE3+ ionic radius. In addition, microstructures and mechanical properties are highly dependent on the RE2O3 additives. With the increase in RE3+ ionic radius, Si2N2O changes from platelike crystals to elongated crystals. The samples doped with La2O3 and Sm2O3 with elongated crystals exhibit higher flexural strength and higher Vickers hardness. 相似文献