SiO_2凝胶玻璃中Eu~(3+)、Tb~(3+)与1,10-邻菲罗啉配合物的原位化学合成及其荧光和热学性能

应用原位化学复合方法，将Eu3＋、Tb3十与1；10-邻菲罗啉配合物光学均匀复合到SiO2凝胶玻璃中，解决了因稀土含氮配合物易水解而难以用溶胶-凝胶工艺将其均匀掺入无机基质的问题研究了原位配合物的荧光和热学性能结果表明，由于配合物的形成使稀土离子特征荧光强度显著增加，而无机基质的保护作用则使原位配合物的热稳性提高200℃以上化学合成纯配合物Eu（Phen）2Cl3·2H2O的高分辨荧光谱表明，Eu3+在其中的格位对称性为C1或C2或C3．     

Dy3+:Y3Al5O12粉体的制备及发光性能研究

采用溶胶-凝胶/燃烧合成法制备了不同Dy3+掺量的Y3Al5O12发光体.分析了基质晶体结构、Dy3+掺量、Re3+的电荷半径比(Z/r)对Dy3+发光强度及发光颜色的影响.结果表明,Dy3+:Y3Al5O12样品的激发主峰位于353nm(6H15/2→6P7/2)附近;由于Dy3+所占据的Y3+位置具有D2对称性,具有一个反演对称中心,使得Dy3+的发射光谱以481nm蓝光发射为发射主峰,但黄蓝光发射强度之比(Y/B)随Dy3+离子浓度的变化很小.     

稀土配合物/改性MCM-41杂化发光材料的合成研究

采用水热法合成了改性MCM-41中孔分子筛;采用液相沉淀法合成了Eu(Phen)2(Pht)2Cl.H2O和Eu(Phen)2(Sal)(Pht)Cl.H2O两种稀土有机配合物。并将所制备的稀土有机配合物组装到改性MCM-41中,合成了稀土配合物(铕)/改性MCM-41杂化发光材料,采用小角XRD、红外光谱、荧光光谱和TEM、N2吸附-脱附对其结构和荧光性质进行了研究。结果表明,组装体具有MCM-41典型结构并且在组装之后仍保留了MCM-41的孔道结构;其荧光光谱具有Eu3+的特征荧光发射,发光强度大于纯配合物,更有利于实际应用。     

Ce3+激活锂-6闪烁玻璃XPS能谱研究

采用XPS能谱分析了不同熔制气氛下制备的锂-6玻璃闪烁体表面结构与Ce离子价态变化情况,研究结果表明锂-6玻璃闪烁体中,激活剂离子Ce3+未进入到玻璃网络结构中,以填充离子的形式分布在网络间隙中;O离子在锂-6玻璃闪烁体中以桥氧和非桥氧两种形式存在,而且随着玻璃配合料中还原剂C粉的掺量增加,非桥氧数量减少;采用XPS半定量计算出不同熔制气氛下锂-6玻璃闪烁体中Ce3+与Ce4+相对含量,为进一步优化其制备工艺技术提供了重要的理论参考依据。     

热处理制度对Pr3+-Yb3+掺杂氟氧微晶玻璃光谱特性的影响

氟氧化物微晶玻璃具有良好的机械性能、化学稳定性和优异的发光性能,是作为量子剪裁的理想介质材料。本文选择55SiO2-5Na2O-20Al2O3-20CaF2作为稀土掺杂的基础玻璃,通过对玻璃进行不同的热处理从而获得了不同的Pr3+-Yb3+共掺微晶玻璃。通过吸收光谱、发射光谱和荧光衰减曲线的比较,发现升高热处理温度或延长保温时间会导致近红外区域的发射峰增强,Pr3+的荧光寿命降低,且计算表明,Pr3+-Yb3+之间的能量传递效率增加了。     

掺Er3+的20PbF2-20GaF3-15InF3-20CdF2-15ZnF2-10SnF2玻璃系统的上转换发光性质研究

制备了掺Er3+的20PbF2-20GaF3-15InF3-20CdF2-1 5ZnF2-10SnF2玻璃系统,研究了Er3+离子含量的变化对玻璃上转换发光性能的影响,探讨了761nm激发下玻璃上转换发光的机理.结果表明,在761nm激发下,可以观察到很强的408nm紫色荧光,并且同时观察到了545nm和523nm的绿色荧光.为掺稀土重金属氟化物玻璃应用于短波长上转换激光器提供了依据.     

Schiff碱稀土配合物以共价键连接方式组装到介孔块体材料的研究

将3-氨丙基三乙氧基硅烷(APTES)与水杨醛在室温下合成有机配体,用于与稀土离子(Tb3+、Sm3+、Dy2+)配位,制得了3种稀土有机配合物.用"后合成法"将稀土配合物以共价键结合的方式连接到以硅基介孔块体为主体的材料上得到组装材料.通过红外光谱、元素分析、BET分析及荧光光谱分析对稀土配合物及其组装材料的组成、结构及性能进行了表征.结果表明,与纯配合物相比,在组装体材料中(Tb3+、Sm3+组装)有机配体的发射峰强度变弱,而稀土离子的特征发射峰强度变强.这表明在组装体材料中从有机配体到稀土离子的能量传递变得更加有效.     

掺铒铋酸盐玻璃光谱性质的混合形成体效应

测得了Er3+离子在铋酸盐玻璃系列(50～75)Bi2O3-(20～45)B2O3-5Na2O,70Bi2O3-(17～25)B2O3-xZrF4-5Na2O,70Bi2O3-(0～25)B2O3-(0～25)SiO2-5Na2O中的吸收光谱、荧光光谱及4I13/2能级荧光寿命.提出并研究了Er3+离子光谱性质的混合形成体效应,结果表明Er3+离子在铋酸盐玻璃中通过混合形成体效应可以获得较大的有效线宽(△λeff＝62～80nm)、较高的受激发射截面(σe＝0.76～0.84×10-20cm2)、较宽的荧光半高宽(FWHM＝55～80nm)以及较长的荧光寿命(τm＝1.6～4.3ms),说明掺Er3+铋酸盐玻璃是光纤放大器实现宽带和高增益放大较为理想的基质材料.     

稀土离子在硼铝玻璃结构中的作用

利用NMR、DSC及热膨胀等测试分析手段,分析了B2O3-Al2O3～BaO玻璃中不同掺量稀土氧化物对11B和27Al的配位及玻璃热学性能的影响规律.结果表明:当稀土含量逐渐增加时,硼氧三角体[BO3]逐渐向[BO4]转变;原先[AlO4]、[A1O5]、[AlO6]共存的铝氧多面体结构单元逐渐转变为以[AlO4]为主和少量[AlO5]共存的结构;玻璃的相转变温度升高,玻璃低温相转变困难.另外,随着稀土氧化物掺量不断增加,N系列玻璃网络结构的连接削弱,玻璃的析晶热稳定性和热膨胀率均有所降低.     

YAG:Yb~(3+),Tm~(3+)纳米晶粉体的制备及其蓝色上转换发光

以稀土氧化物、硝酸铝为原料,采用溶胶-凝胶法合成了Yb3+、Tm3+共掺的钇铝石榴石(Y3Al5O12,YAG)纳米晶粉体。采用X射线衍射(XRD)确定了1200℃煅烧后的晶体粉为纯YAG结构,无杂质相,晶体尺寸约为90nm;该粉体在波长为980nm的半导体激光器激发下发射出中心波长为487nm的蓝色上转换荧光,对应于Tm3+离子的1G4→3H6的跃迁。发光强度和激发功率关系的研究揭示了其为双光子过程,Tm3+的激发态吸收及Tm3+、Yb3+间的交叉驰豫型能量传递和是该上转换发光的主要机制。     

稀土对Al-Zn-M g-Cu/Al2O3陶瓷界面润湿性的影响

采用真空座滴法和熔铸法研究了在Al-Zn-Mg-Cu 合金中加入稀土(Ce、Y) 对Al2Zn2M g2Cu/Al₂O₃陶瓷界面润湿性的影响。结果表明,Al-Zn-Mg-Cu 合金中加入稀土可有效降低铝合金/Al₂O₃界面的接触角, 改善界面结合状态; 稀土改善界面润湿性存在一最佳含量范围, 添加Ce 的最佳含量约为0. 5w t% , Y 约为0. 7w t%。稀土改善润湿性的作用主要是稀土与Al₂O₃膜、Al₂O₃陶瓷发生反应。Mg、Zn、Cu 等合金元素在界面富集并参与界面反应对润湿性有利; 稀土与Mg、Zn、Cu 等合金元素适当组合改善润湿性的效果比单一稀土明显。      

The luminescent properties, thermal stability of phthalic acid and energy transfer from phthalic acid to Tb in sol—gel derived silica xerogels

In recent years, the energy transfer between different rare earth ions and the luminescent properties of rare earth ions have been studied extensively. However, the research of luminescent properties, thermal stability and structural variations of organic compounds, as well as their energy transfer to rare earth ions in silica xerogel, have not been reported. Organic—inorganic composites have even more efficient luminescence than pure rare earth ions. We describe the fabrication of silica xerogels doped with phthalic acid and Tb³⁺, their luminescent properties and thermal stability. The results show that, in silica xerogels, phthalic acid can exist steadily at 300 °C, and it can transfer the energy that it has absorbed to Tb³⁺.     

Fabrication and optical features of the sol–gel derived silica glasses doped with copper oxide nanoparticles and europium

Novel sol–gel derived silica glasses doped with copper oxide nanoparticles and europium ions have been fabricated in order to design a multicomponent luminescent material. The photoluminescence studies indicated the significant effect of copper oxide upon the light emission due to europium ions while the emission from copper oxide is similar with that due to Cu⁺. The emission of europium ions in the Cu₂O:Eu³⁺-codoped glasses can be done through excitation of copper oxide.     

纳米复合1.3μm光放大材料的荧光和吸收谱

纳米级掺稀土非氧化物团簇复合在氧化硅玻璃中,可以结合非氧化物玻璃和氧化物玻璃在光放大和化学、热力学、力学等方面各自的优点,提供可以应用于实用化1.3μm,宽带1.5μm和新发展的1.4μm光放大的新材料.在一种复合材料中,峰值位于1315nm的荧光峰及线型被证实与用来进行复合的掺稀土氟镓锆玻璃中的峰完全一致,而在复合材料中其荧光寿命较长.以Pr3+和Nd3+作为活性离子的复合材料的吸收谱线宽比Pr3+和Nd3+掺杂的ZBLAN的相应吸收谱线宽展宽最多达到10nm.复合材料的光谱性质有利于器件增益并放宽对泵浦光源的要求.     

Improved photoluminescence and ferroelectric properties of (Bi(3.6)Eu(0.4))Ti₃O₁₂ thin films via Li+ doping

(Bi(3.6)Eu(0.4))Ti?O?? (BEuT) thin films with different Li+ doping contents were prepared on fused silica and Pt/Ti/SiO?/Si substrates by chemical solution deposition, and the effects of Li+ doping contents on the photoluminescence and ferroelectric properties of the thin films were investigated in detail. The results showed that an appropriate amount of Li+ doping could effectively improve emission intensities for two characteristic Eu3+ emission transitions of ?D?→?F? (594 nm) and ?D?→?F? (617 nm) compared with BEuT thin films without Li doping. This photoluminescence improvement can be attributed to the dual roles of Li+ ions, one of which is that Li ions can act as co-activators which are helpful to the energy transfer from the host to the Eu3+ ions, leading to a higher quantum yield; the other is that Li ion doping can induce local distortion of crystal field surrounding the Eu3+ activator because Bi3+ and Li+ ions have different ionic radii. In addition, the Li+-doped BEuT thin films had larger remanent polarization than BEuT thin films without Li doping prepared under the same experimental conditions. These results suggest that Li+ doping is an effective way to improve photoluminescence and ferroelectric properties of the (Bi,Eu)?Ti?O?? thin films.     

Optical absorption of Nd, Sm and Dy in bismuth borate glasses with large radiative transition probabilities

This paper reports on the optical properties of Nd³⁺, Sm³⁺ and Dy³⁺ in bismuth borate glasses, with Bi₂O₃ content varying from 30 to 60 mol%. The variation of the optical properties with composition plays a dominant role in determining a good laser host material. The variation of the Judd–Ofelt intensity parameters Ω_t (t=2,4,6) and the radiative transition probabilities and the hypersensitive band positions, with composition, have been discussed in detail. The changes in position and intensity parameters of the transitions in the optical absorption spectra are correlated to the structural changes in the host glass matrix. The variation of Ω₂ with Bi₂O₃ content has been attributed to changes in the asymmetry of the ligand field at the rare earth ion site and to the changes in their rare earth–oxygen (R–O) covalency, whereas the variation of Ω₆ strongly depends on nephlauxetic effect. The shift of the hypersensitive band shows that the covalency of the R–O bond increases with increase of Bi₂O₃ content, due to increased interaction between the rare earth ions and the non-bridging oxygens. The radiative transition probabilities of the rare earth ions are large in bismuth borate glasses, suggesting their suitability for laser applications.     

新型铝改性硅胶吸附材料的制备与性能

陶瓷纤维纸经水玻璃、酸性铝盐溶液顺次浸渍得到新型铝改性硅胶吸附材料．反应的优化条件为：水玻璃浓度26．6wt％、铝盐浓度10wt％、溶液pH值1．8．^29Si和^27AlMAS NMR谱显示：铝替代硅进入SiO4硅氧四面体结构单元，但并不影响其骨架结构；红外光谱显示Si—OH对称伸缩振动峰由968cm^-1移至Si(Al)-OH的954cm^-1；扫描电镜图表明铝改性硅胶能较好地分散在瓦楞陶瓷纤维表面及其孔隙中；X射线能谱(EDS)揭示材料表面微区Al^3 的存在与含量,孔隙分析显示材料起吸附作用的主要为中孔；由于铝离子改性，新型吸附材料的吸附性能、耐热性能及机械强度等均优于同等条件下反应生成的硅胶．     

Tb3+/Yb3+ codoped silica–hafnia glass and glass–ceramic waveguides to improve the efficiency of photovoltaic solar cells

In this paper we present the investigation of the energy transfer efficiency between Tb³⁺ and Yb³⁺ ions in silica–hafnia waveguides. Cooperative energy transfer between these two ions allows to cut one 488 nm photon in two 980 nm photons and could have important applications in improving the performance of photovoltaic solar cells. Previous works revealed that for a given concentration of donors (Tb³⁺), increasing the number of acceptors (Yb³⁺) located near to the Tb³⁺ ion can increase the Tb–Yb transfer probability. However, when increasing the density of active ions, some detrimental effects due to cross-relaxation mechanisms become relevant. On the basis of this observation the sample doping was chosen keeping constant the molar ratio [Yb]/[Tb] = 4 and the total rare earths contents were [Tb + Yb]/[Si + Hf] = 5%, 7%, 9%. The choice of the matrix is another crucial point to obtain an efficient down conversion processes with rare earth ions. To this respect a 70SiO₂–30HfO₂ waveguide composition was chosen. The comparison between the glass and the glass–ceramic structures demonstrated that the latter is more efficient since it combines the good optical properties of glasses with the optimal spectroscopic properties of crystals activated by luminescent species. A maximum transfer efficiency of 55% was found for the highest rare earth doping concentration.     

Stark level analysis for Er-doped ZBLAN glass

From the absorption and emission spectra recorded in a conventional way at 13 K, the Stark levels in manifolds from ⁴I_15/2 to ²H_9/2 for Er³⁺-doped ZBLAN (ZrF₄–BaF₂–LaF₃–AlF₃–NaF) glass have been investigated by means of the effective crystal field model previously proposed to describe the average of local symmetries occupied by rare earth ions in oxide glasses [1]. This model, based on the principle of descending symmetry, used the symmetry group chain scheme. Crystal field strength, homogeneous and inhomogeneous widths of levels have been determined, and the former models and results about optical properties for rare earth ions in heavy metal fluoride glasses are discussed. In fluoride glasses, the rare earth ions appear more evenly distributed than in oxide glasses, and the crystal field strength is weaker than in oxide glasses.     

掺稀土离子玻璃的光放大效应

光放大材料是光纤放大器的主要组成部分，它决定光纤放大器的光放大功率。本文介绍了掺稀土离子如Er^3 、Nd^3 、Pr^3 及Dy^3 等玻璃的光放大原理以及影响光放大的各种因素。稀土离子本身存在的多种发射跃迁、无辐射跃迁，稀土离子间相互作用以及玻璃基质都影响稀土离子的光放大跃迁效率。上述分析对掺稀土离子玻璃的光放大材料性能的改进和新材料的设计可提供有益的指导。