Dy~(3+)/Tb~(3+)掺杂高钆镥闪烁玻璃光谱性能

用高温熔融法制备了Dy3+/Tb3+掺杂的高钆镥氟氧化物闪烁玻璃样品,测试分析了其吸收光谱、激发与发射光谱及衰减曲线等。研究了Dy3+和Tb3+离子浓度增加对Tb3+离子发光的影响以及Dy3+离子的浓度猝灭效应;通过IH理论模型分析了Dy3+和Tb3+离子的能量传递方式和能量传递效率。结果表明Dy3+离子对Tb3+离子发光具有敏化作用,随着Dy3+离子浓度增加敏化作用增强,但是当Dy3+离子的浓度达到2%(摩尔分数)以上时,随着Dy3+离子浓度的增加,Tb3+离子的发光强度降低;Dy3+和Tb3+离子的能量传递方式为无辐射能量传递方式,且能量传递效率可以达到60%以上。     

微晶玻璃的制备与光谱特性

高温熔制摩尔组分为32CaO-12Y₂O₃-24Al₂O₃-31SiO₂-1Yb₂O₃的玻璃, 制得的玻璃于950、1050、1100℃三个不同温度进行热处理, 用XRD分析热处理后样品的相变, 用TEM观察1050℃热处理后的样品, 并研究了1050℃热处理前后样品的光谱特性. 研究结果表明: 玻璃在1050℃热处理后, 在玻璃中产生单一YAG相微晶颗粒; 热处理前后样品光谱特性的变化表明热处理后掺杂的Yb ³⁺离子择优进入到YAG晶格位, 制备得到了透明Yb:YAG微晶玻璃.     

用光刻、软刻和氧化硅球晶体模板制备表面微结构

表面微结构的制备对获得超疏水性表面和改善生物医学材料性能具有重要意义. 为了制备微米、亚微米和纳米级表面微结构, 本文采用光刻(photo-lithography)和软刻技术(soft lithography) 制备了微米尺寸长方体或圆柱体的阵列, 压印出变形长方体(塔状)或圆柱体(圆盘状)阵列的微结构表面; 采用单分散氧化硅球自集聚紧密堆积而成的胶体晶体为模板, 制备了亚微米/纳米 尺寸网状微结构的表面. 用光学和扫描电子显微镜表征了所获得的表面微结构.     

White light emission from Dy3+-doped LiLuF4 single crystal grown by Bridgman method

Lithium lutetium fluoride （LiLuF4） single crystals doped with different Dy3＋ ion concentrations were grown by Bridgman method. The Judd-Ofelt （J-O） strength parameters （Ω2, Ω4, Ω6） of Dy3＋ in LiLuF4 crystal are calculated according to the measured absorption spectra and the J-O theory, by which the asymmetry of the Dy3＋：LiLuF4 single crystal and the possibility of attaining stimulated emission from 4F9/2 level are analyzed. The capability of the Dy3＋：LiLuF4 crystal in generating white light by simultaneous blue and yellow emissions under excitation with ultra- violet light is produced. The effects of excitation wavelength and doping concentration on chromaticity coordinates and photoluminescence intensity are also investigated. Favorable CIE coordinates, x=0.319 3 and y=0.349 3, can be obtained for Dy3＋ ion in 2.701% molar doping concentration under excitation of 350 nm.     

GdFeCo/AIN/DyFeCo静磁耦合多层薄膜磁化方向转变的研究

对GdFeco／AIN／DyFeco静磁耦合多层薄膜变温磁化方向变化进行了研究。结果表明读出层GdFeCo随温度上升从平面磁化转变成垂直磁化，转变过程中受饱和磁化强度(M)和有效各向异性常数影响，但主要受饱和磁化强度(M)的影响。在高温时读出层的磁化强度很小，退磁场能减小，在静磁耦合作用下，使GdFeCo读出层的磁化方向发生转变，而且磁化方向的转变在较小的温度范围内变化较快。     

Sol-gel法制备(BiAl)DyIG石榴石磁光记录薄膜

采用柠檬酸络合物型溶胶 凝胶法首次制备得到了具有垂直各向异性的(BiAl)DyIG石榴石磁光记录薄膜,并对材料结构和磁光性质进行了研究,结果得到石榴石磁光记录薄膜磁滞回线具有较好的矩形比,在430nm和520nm的品质因子为2°和1.5°,最佳晶化温度为675℃。     

NiMn1.5Fe0.5-χTiχO4系热敏电阻的制备与性能研究

用传统的高温固相烧结法制备了NiMn1.5-χFe0.5-χTiχO4(0<χ≤0.5)系列负温度系数(NTC)热敏电阻.通过X射线衍射分析、SEM、阻值测量等手段研究了TiO2组份对MnNiFe热敏电阻材料的晶相结构、微观形貌与电学性能的影响规律.结果表明:TiO2的加入并没有改变热敏电阻的典型尖晶石相结构,但是随着TiO2的加入,明显发现其烧结后陶瓷微晶粒变小而致密,这大概是由于掺入到晶格中的TiO2物质在烧结过程中起到迟缓晶粒生长的作用所致.在MnNiFeO系热敏电阻材料中掺入TiO2后,明显地改善了MnNiFe热敏电阻材料的阻温(电阻随温度)特性并提高了电学性能的稳定性.     

Enhanced cooperative near-infrared quantum cutting in Pr3+-Yb3+ co-doped phosphate glass

Pr3+and Yb3+co-doped phosphate glasses are prepared to study their optical properties.Excitation and emission spectra and decay curves are used to characterize their luminescence.We demonstrate that upon excitation of Pr3+ion with one high energy photon at 470 nm,two near-infrared(NIR)photons are emitted at 950-1100 nm(Yb3+:2F 5/2 →2F 7/2)through an efficient cooperative energy transfer(CET)from Pr3+to Yb3+.The maximum energy transfer efficiency(ETE)and the corresponding quantum efficiency approach up to 90.17%and 190.17%,respectively.The glass materials might find potential application for improving the efficiency of silicon-based solar cells.     

Co2+,Zn2+双掺杂铌酸锂晶体的坩埚下降法生长及其光谱特性

在LiNbO3中掺入0．1％（摩尔分数．下同）的CoO与3％,6％的ZnO,采用坩埚下降法技术生长了双掺杂的Co^2＋：Zn^2＋：LiNbO3晶体。用X射线衍射与差热分析表征了获得的晶体。测定了晶体不同部位在350～2500nm波段的吸收光谱。研究表明：Co离子位于LiNbO3晶体的崎变的氧八面体中,呈现＋2价,沿着生长方向Co^2＋在晶体中的浓度逐渐减少。ZnO的掺杂有效地抑制了Co^2＋离子在晶体中的掺入,使得Co^2＋在晶体中浓度的分布变得均匀。同时发现：ZnO的掺入使得上部晶体的熔点升高。从化学组分的角度解释了产生熔点变化的原因。观测到了750nm波长的荧光发射带。[编者按]     

Optical Spectroscopy of Er^3＋ and Er^3＋/Yb^3＋ Co-doped Bi2O3-GeO2-B2O3-ZnO Glasses

The （60 - x）Bi2O3 - xGeO2-30B2O3-10ZnO （x = 5, 10, 20, 30 molar percent） glasses doped with Er^3＋ and Er^3＋/Yb^3＋ were fabricated using the melting method. The thermal stability of the glasses was studied with their DTA curves. The results show that the difference between the glass transition temperature and the crystallization onset temperature increases with the increase of GeO2 content, indicating that the thermal stability of the glass has become better. The absorption spectra were recorded and the stimulated emission cross sections were calculated using the McCumber theory. The Ω2, O4, and Ω6 parameters,the transition probability, the radiative lifetime, and the fluorescence branch ratio of Er^3＋ for optical transition were calculated from their absorption spectra in terms of reduced matrix U^（t）（λ = 2, 4, 6） character for optical transitions. The infrared emission of Er^3＋ was measured upon excitation with 970 nm light and the full width at half-maximum （FWHM） was estimated from the emission spectra. The pumping efficiency and the intensity of the emission at the 1.54 μm band of Er^3＋ were enhanced considerably by co-doping Yb^3＋ .