无容器制备Er3+/Yb3+共掺La2O3-TiO2-ZrO2玻璃及其上转换发光研究

利用无容器技术制备了(La_0.94-xEr_0.06Yb_x)(Ti_0.95Zr_0.05)_2.25O₆(x=0~0.24, 间隔0.04)球状透明玻璃, 其稀土离子掺杂浓度最大值达到30%。通过DTA分析发现, 玻璃具有很好的热稳定性, x=0时玻璃化转变温度T_g和析晶起始温度T_o分别为818℃和906℃, ΔT(ΔT= T_o-T_g)为88℃, 玻璃形成能力较低。随着Yb³⁺浓度提高, T_g、T_o和ΔT逐渐下降, 说明Yb³⁺降低了玻璃的热稳定性和形成能力。利用紫外可见分光光度计测定了样品的吸收/透过光谱, 玻璃在975 nm具有很强的吸收峰, 表明Yb³⁺可以有效提高玻璃对入射光的吸收强度; 在可见光范围内除特征吸收外具有近70%的透过率, 说明玻璃具有良好的透可见光性能, 有望获得高强上转换发光输出。上转换荧光光谱研究表明: 在980 nm激光泵浦下, 获得了中心位于535、554和672 nm处的绿、红发光带, x=0.16的发光最强, 672 nm处的红光强度是x=0的近130倍。上转换发光强度与泵浦功率关系的分析表明: 535、554 nm处的绿光和672 nm处的红光发光均是双光子发光过程。     

Nd3+/Yb3+共掺La2O3-TiO2-ZrO2微晶玻璃的制备及上转换发光研究

利用气悬浮方法制备了Nd³⁺/Yb³⁺共掺La₂O₃-TiO₂-ZrO₂前驱体玻璃, 通过热处理获得了微晶玻璃。通过DTA对前驱体玻璃的热稳定性进行了研究。利用光致发光谱, TEM和EDS对微晶玻璃进行了表征分析, 并研究了热处理对上转换发光的影响。结果表明: 玻璃转变温度和析晶起始温度分别为799℃和880℃. 在980 nm激光激发下, 样品发射出中心位于497, 523, 545, 603和657 nm处的五条发光带。热处理后样品上转换发光强度提高, 经过880℃保温50 min热处理的微晶玻璃显示了最强的上转换发光, 在545 nm处的发光强度是前驱体玻璃的11倍, 这是由于在微晶玻璃基质中存在致密柱状晶和Nd³⁺离子在晶体中富集造成的。     

Al3+/Yb3+/P5+掺杂对石英玻璃紫外透过和紫外激发荧光的影响

采用溶胶-凝胶法结合高温真空烧结工艺制备了不同浓度的Al³⁺/Yb³⁺/P⁵⁺掺杂石英玻璃。研究了P⁵⁺和Al³⁺的引入对Yb³⁺掺杂石英玻璃紫外透过和紫外激发荧光光谱, 以及Yb4d电子结合能的影响, 并初步探索了其机理。研究结果表明, Al³⁺/Yb³⁺/P⁵⁺掺杂石英玻璃在190~300 nm波段的吸收主要来源于O^2-→Yb³⁺的电荷迁移吸收, 其谱带位置和Yb4d电子结合能随Yb³⁺的第二配位元素(Al、Si、P)电负性增大向高能方向移动。真空烧结条件下, 引入Al³⁺会引发石英玻璃中Yb³⁺还原为Yb²⁺, 其典型的吸收峰位于330 nm处; 然而, 在Al³⁺/Yb³⁺共掺的基础上再引入P⁵⁺, 且P⁵⁺/Al³⁺摩尔比大于1时, 可以有效抑制Yb²⁺的形成。紫外光激发引起的近红外发光(976 nm)是电子从电荷迁移态弛豫到Yb³⁺激发态向基态跃迁的结果, 可见发光(525 nm)归因于Yb²⁺的5d→4f跃迁。本文研究结果对通过优化工艺和调整组分制备出高性能的Yb³⁺掺杂光纤具有一定的指导意义。     

Yb3+-Tm3+共掺BiOBr纳米晶的近红外上转换发光特性研究

采用水热法合成了Yb³⁺-Tm³⁺共掺BiOBr纳米晶, 研究了其上转换发光性能。在980 nm光激发下, 样品中Tm³⁺离子实现了³H₄→³H₆、¹G₄→³F₄和¹G₄→³H₆跃迁, 进而发出强烈的近红外光(801 nm)和较弱的红光(655 nm)与蓝光(485 nm)。探讨了样品的上转换发光机理, 上转换发光强度与激发功率的关系表明在980 nm激发下Tm³⁺的蓝光和红光发射为三光子过程, 而近红外发光为双光子过程。随着Yb³⁺浓度增加, 近红外发光显著增强, 近红外光与蓝光(I_{801 nm}/I_{485 nm})的发光强度比高达71.4。研究结果表明, Yb³⁺-Tm³⁺共掺BiOBr纳米晶在生物荧光标记领域具有潜在的应用前景。     

Gd2O3下转换发光材料的制备及光学性能研究

通过溶胶-凝胶法制备了Er³⁺/Yb³⁺双掺杂的Gd₂O₃下转换发光材料,按照掺杂摩尔百分比n(Gd³⁺)∶n(Er³⁺)∶n(Yb³⁺)=100∶2:x（x=0,3,6,9）调整Yb³⁺的掺杂比例,通过XRD、SEM、荧光光谱和荧光衰减研究了Er³⁺/Yb³⁺双掺对Gd₂O₃发光材料晶体结构、微观形貌、发光性能和量子传递效率的影响。结果表明,Er³⁺/Yb³⁺的掺杂没有改变Gd₂O₃的晶体结构,但使样品的特征衍射峰出现了高角度偏移;所有样品的晶粒尺寸约为65～85 nm,均属于纳米材料;随着Yb³⁺掺杂量的增加,样品在可见光区域和近红外光区域的衍射峰强度均表现出先升高后降低的趋势,其中2Er:3Yb掺杂比例的Gd     

MF2(M=Mg,Ca,Zn,Sr,Ba)对掺Yb3+磷酸盐玻璃性质的影响

熔制了60P₂O₅·6Al₂O₃·(33-x)BaO·xBaF₂·1Yb₂O₃(x=0,3,6,9)和60P₂O₅·6Al₂O₃·27BaO·6MF₂·1Yb₂O₃(M=Mg、Ca、Sr、Zn、Ba)(分子分数)玻璃,测试了其折射率、密度、转变温度、析晶温度、熔点温度、红外光谱和紫外吸收光谱,讨论了二价氟化物MF₂(M=Mg、Ca、Sr、Zn、Ba)对磷酸盐玻璃热稳定性及内部结构的影响,测试了Yb³⁺离子的吸收光谱、荧光光谱、荧光寿命,计算了光谱参数,讨论了MF₂对Yb³⁺磷酸盐玻璃光谱性质的影响,结果表明二价金属氟化物是作为网络外体进入到磷酸盐玻璃结构中,并没有改变磷酸盐玻璃内部的[PO₄]链状结构,二价金属氟化物还有助于提高Yb³⁺离子的受激发射截面,和自发辐射几率,荧光半高宽。     

(Lu0.5In0.5)2O3:Tm3+,Yb3+超细粉末的合成和上转换发光

先用液相沉淀技术合成Lu/In/Tm/Yb四元体系水合碱式碳酸盐类沉淀前驱体,然后将其在1100℃煅烧制备出一系列类球状平均粒度约为110 nm的[(Lu_0.5In_0.5)_0.999-xTm_0.001Yb_x]₂O₃ (x=0~0.05)氧化物固溶体。在980 nm泵浦激光激励下这种氧化物粉体在可见光区发射出强烈的蓝青光(450~510 nm,源于Tm³⁺离子4f¹²电子组态内¹D₂→³H₆,³F₄电子跃迁)和较弱的红光(650~670 nm,源于Tm³⁺离子的¹G₄→³F₄电子跃迁),二者的上转换过程均为双光子吸收。随着Yb³⁺离子浓度的提高1931CIE色坐标上的发射光颜色逐渐由绿光(0.31, 0.54)移向蓝光(0.01, 0.19)。Yb³⁺离子共掺提高了Tm³⁺离子的上转换发光强度,其最佳含量为2.5%。发射474 nm蓝光和654 nm红光的粉体,其荧光寿命分别约为0.84和0.97 ms。     

Eu3+掺杂硼酸盐玻璃的发光性质及其热稳定性研究

荧光玻璃具有发光中心分布均匀和热稳定好等优点, 成为LED领域研究的热点。本研究采用传统的高温熔融淬火法合成了一系列Eu³⁺掺杂的硼酸盐玻璃, 通过荧光光谱手段对其发光性质及热稳定性进行了表征; 利用Van Uitert模型对样品中Eu³⁺的浓度猝灭行为进行了研究。结果表明: 样品中Eu³⁺的浓度猝灭机理为Eu³⁺离子间的交换作用导致的无辐射能量传递; 利用Arrhenius公式对荧光玻璃样品的温度猝灭行为进行了分析。结果表明: 样品中Eu³⁺的发光温度猝灭属于Crossover过程; 最后分析了Eu³⁺与荧光玻璃基质之间的相互作用。     

γ辐照及热退火对光热折变玻璃光学性能的影响

对光热折变(Photo-thermal-refractive, PTR)玻璃在总剂量分别为0.35、1、10及100 kGy的γ射线下辐照, 并进行热退火处理, 采用吸收光谱、光致发光光谱及EPR电子顺磁共振谱研究了光热折变玻璃在γ射线辐照下的辐照机理。研究结果表明, γ辐照后的PTR玻璃在可见波段的吸收主要由银原子Ag⁰、银分子簇Ag₂、银分子簇Ag₃、银纳米颗粒Ag_m⁰及非桥氧空穴中心HC₁及HC₂引起; 在不同剂量γ射线辐照下, 玻璃基质中的变价离子(Ag⁺、Ce³⁺)价态先发生变化, 同时玻璃基质中的非桥氧键发生电离, 形成了非桥氧空穴型缺陷中心HC₁、HC₂。进一步增加辐照剂量, 产生了银的分子簇Ag₂和Ag₃; 同时玻璃基质中非桥氧空穴中心HC₂的浓度增大, 导致在639 nm附近的吸收增强。分别在不同温度下对辐照后的PTR玻璃进行相同时间的热处理及在低于T_g(玻璃转变温度)的温度下进行不同时间的热处理, 观察到250 ℃退火后PTR玻璃中HC₁及HC₂缺陷中心发生漂白; 并在430 ℃退火后出现了银纳米颗粒的吸收峰, 该吸收峰随退火时间的延长发生了红移及展宽。     

掺铈多组分硅酸盐玻璃电子辐照着色研究

采用吸收光谱、电子顺磁共振谱和光致发光谱对掺Ce多组分硅酸盐玻璃K509在10 MeV电子辐照下的色心动力学进行了研究。结果表明, 电子辐照引起K509玻璃可见光透过率降低的色心类型为非桥氧空穴色心HC1和HC2。在剂量率一定的情况下, 色心浓度随总剂量的增大呈指数函数增大; 在总剂量一定的情况下, 色心浓度随剂量率增大呈指数函数减小。Ce³⁺荧光强度的变化表明辐照过程中Ce³⁺浓度与辐照总剂量负相关, 与辐照剂量率正相关, 验证了掺Ce玻璃耐辐照机理: Ce³⁺吸收辐照产生的空穴从而抑制空穴色心HC1和HC2的形成, 且不引入额外的可见光波段吸收。通过对Ce³⁺宽带荧光峰进行高斯拟合, 得到了K509中Ce³⁺能级结构图。     

Emission Properties of Yb3+/Er3+ Doped TeO2-WO3-ZnO Glasses for Broadband Optical Amplifiers

The YbS /Er3 doped TeO2-WO3-ZnO glasses were prepared. The absorption spectra, emission spectra and fluorescence lifetime of Era at 1.5μm, excited by 970 nm were measured. The influence of Er2Oa, Yb2Oa and Ohcontents on emission properties of Era at 1.5 μm was investigated. The optimum doping concentrations for Era and Yba is around 3.34× 1020 ions/cma and 6.63×1020 ions/cma, respectively. The peak emission cross section is 0.83～0.87 pm2. With the increasing concentration of Yba , the FWHM of Era emission at 1.5 μm in the glass increases from 77 nm to 83 nm. The results show that Yba /Era doped meO2-Woa-ZnO glasses are promising candidate for Era -doped broadband optical amplifier.     

Valency states of Yb, Eu, Dy and Ti ions in Li2B4O7 glasses

Absorption and emission spectra of Eu and Dy, Yb and Ti ions in Li₂B₄O₇ glasses grown in oxygen and hydrogen gas atmospheres were measured for valency states and lattice-sites analysis. For the Li₂B₄O₇ glass doped with Eu²⁺, Eu³⁺ and Dy³⁺ ions which were grown in oxidizing and reducing atmospheres, absorption and emission bands due to these ions were investigated before and after γ-irradiation. For the Yb³⁺-doped Li₂B₄O₇ glass, a weak, broad band was observed near the sharp 976.3 nm absorption band. The origin of this band is discussed in comparison with other glasses. Moreover, irradiation experiments using γ-rays were also performed in order to investigate the possibility of valency change of Yb ions. It was found that Ti⁴⁺ ions, which are produced under oxidizing atmosphere, change to Ti³⁺ ions after γ-irradiation with a dose of 10⁵ Gy. An additional absorption band observed at about 500 nm is due to the Ti³⁺ ions accompanied by charge-compensating vacancy and does not give any emission.     

稀土掺杂上转换发光玻璃陶瓷的制备及性能

实验制备了一类含有SrF2∶Yb3+,Tm3+及SrF2∶Yb3+,Er3+的透明发光玻璃和玻璃陶瓷,对比研究了热处理工艺对玻璃陶瓷相组成、微观结构和光谱性能的影响规律。研究表明,玻璃陶瓷具有立方SrF2纳米晶相均匀分布于玻璃基体的复相结构,利用HRTEM可观测到SrF2纳米晶相的(111)晶面,其晶粒尺度在10~30nm之间,且该析晶相中富集有Yb3+/Tm3+和Yb3+/Er3+。基于此,玻璃陶瓷在980nm LD激光激发下的上转换发光强度较玻璃样品有较大提高。其上转换发光机制分别主要为Yb3+-Yb3+之间的合作上转换,Yb3+-Tm3+和Tm3+-Tm3+之间的交叉弛豫能量传递过程,以及Yb3+-Er3+之间的能量传递上转换。     

Energy transfer mechanisms in Yb3+-doped GdVO4 near-infrared downconversion nanophosphor

Yb3+-doped GdVO4 nanophosphor was prepared by the co-precipitation method. Under ultraviolet (UV) light excitation, strong near-infrared (NIR) emission of Yb3+ (2F(5/2) --> 2F(7/2)) around 980 nm was observed. Owing to the host absorption of GdVO4, a broad excitation band ranging from 250 to 350 nm was recorded when the Yb3+ emission was monitored, which suggests an efficient energy transfer from the host to the Yb3+ ions. The concentration dependence of the visible vanadate emission and the Yb3+ emission was investigated. The decay curve of the vanadate emission was measured under the excitation of a 266 nm pulsed laser. The decay time of the vanadate emission at 500 nm was remarkably reduced by introducing Yb3+, further verifying that the energy transfer from the vanadate host to the Yb3+ ions was very efficient. Cooperative energy transfer (CET) is discussed as the possible energy transfer process. The temperature dependence of the emission intensity and decay time were also investigated for our further discussion.     

离子交换法制备波导放大器的磷酸盐铒玻璃研究

研究了不同Al₂O₃、Na₂O、La₂O₃、Y₂O₃及AlF3含量的磷酸盐铒玻璃的物理化学性质和光谱性质,通过恒温水浴失重测试的方法探讨了玻璃组分Al₂O₃、Na₂O、La₂O₃、Y₂O₃及AlF₃对磷酸盐玻璃化学稳定性的影响.结果表明,Al₂O₃含量增加,玻璃化学稳定性提高,添加少量的AlF₃会降低玻璃的化学稳定性,与La₂O₃相比Y₂O₃对提高玻璃的热稳定性有益.通过对比不同组分玻璃样品的热性质、机械性质以及析晶、光谱性质的结果,初步得出了一个比较适于离子交换过程的磷酸盐铒玻璃成分.     

P2O3-B2O3-Al2O3-SrO-BaO玻璃中Yb3+非辐射能量转移下Er3+离子的增强发射

本文研究了共掺Er3 +/Yb3 +P2 O3 -B2 O3 -Al2 O3 -SrO -BaO玻璃的能量转移过程。实验中制备了高掺杂Yb3 +离子的双掺Er3 +/Yb3 +的磷酸盐玻璃样品。在Er3 +/Yb3 +掺杂比率 >1 :1 8(mol% )时 ,观测到了基于Yb3 +离子至Er3 +离子能量转移下Er3 +( 4 I13 / 2 →4I15 / 2 )的增强发射和Yb3 +( 2 F7/ 2 →2 F5 / 2 )发射的减弱 ,当Yb3 +离子掺杂浓度超过 2 .1× 1 0 2 1ions/cm3 时 (Er3 +/Yb3 +≤ 1 :1 8,mol% ) ,由于Yb3 +离子的自淬灭效应 ,Er3 +离子的发射强度降低。实验中得到了Yb3 +离子的最佳掺杂浓度为1 .74× 1 0 2 1ions/cm3     

Influence of Yb-doping on optoelectrical properties of CdO nanocrystalline films

Yb-doped CdO thin films with different Yb contents were prepared on glass and silicon substrates by vacuum evaporation technique. The effects of Yb-doping on the structural and optoelectrical properties of the host CdO films were systematically studied. The X-ray diffraction study shows that some of Yb³⁺ ions substituted for Cd²⁺ and the solubility of Yb in CdO is very limited and may be around ~0.2 at.%. The Yb-doping influences all the optoelectrical properties of CdO. The bandgap of Yb-doped CdO suffers narrowing by about 20% with a very small (0.03 at.%) doping level. The electrical behaviours show that all the prepared Yb-doped CdO films are degenerate semiconductors. Their dc-conductivity, carrier concentration, and mobility increase compared with undoped CdO film. The largest mobility of about 87 cm²/V s was measured for 0.13 at.% Yb-doped CdO film. From transparent-conducting-oxide point of view, Yb is sufficiently effective for CdO-doping.     

The 1.53 μm spectroscopic properties of Er3+/Ce3+/Yb3+ tri-doped tellurite glasses containing silver nanoparticles

The metallic silver nanoparticles (NPs) was introduced into the Er³⁺/Ce³⁺/Yb³⁺ tri-doped tellurite glasses with composition TeO₂–ZnO–La₂O₃ to improve the 1.53 μm band fluorescence. The UV/Vis/NIR absorption spectra, 1.53 μm band fluorescence spectra, fluorescence lifetimes, X-ray diffraction (XRD) curves, differential scanning calorimeter (DSC) curves and transmission electron microscopy (TEM) image of tri-doped tellurite glasses were measured, together with the Judd–Ofelt intensity parameters, emission cross-sections, absorption cross-sections and radiative quantum efficiencies were calculated to investigate the effects of silver NPs on the 1.53 μm band spectroscopic properties of Er³⁺ ions, structural nature and thermal stability of glass hosts. It is shown that Er³⁺/Ce³⁺/Yb³⁺ tri-doped tellurite glasses can emit intense 1.53 μm band fluorescence through the combined energy transfer (ET) processes from Yb³⁺ to Er³⁺ ions and Er³⁺ to Ce³⁺ ions under the 980 nm excitation. At the same time, the introduction of an appropriate amount of silver NPs can further improve the 1.53 μm band fluorescence owing to the enhanced local electric field effect induced by localized surface Plasmon resonance (LSPR) of silver NPs and the possible energy transfer from silver NPs to Er³⁺ ions, and an improvement by about 120% of fluorescence intensity is found in the studied Er³⁺/Ce³⁺/Yb³⁺ tri-doped tellurite glass containing 0.5 mol% amount of silver NPs with average diameter of ∼15 nm. The energy transfer mechanisms from Yb³⁺ to Er³⁺ ions and Er³⁺ to Ce³⁺ ions were also quantitatively investigated by calculating energy transfer microparameters and phonon contribution ratios. Furthermore, the thermal stability of glass host increases slightly with the introduction of silver NPs while the glass structure maintains the amorphous nature. The results indicate that the prepared Er³⁺/Ce³⁺/Yb³⁺ tri-doped tellurite glass with an appropriate amount of silver NPs is an excellent gain medium applied for 1.53 μm band EDFA pumped with a 980 nm laser diode (LD).     

SiO2对掺钕铝酸盐玻璃结构及光谱性质的影响

实验通过高温熔融法制备了不同SiO₂ 浓度的掺钕钙铝酸盐玻璃。采用拉曼光谱法分析玻璃结构变化, 发现随着SiO₂含量的增加, [AlO₄]网格中非桥氧逐渐转移至Si⁴⁺离子周围, 玻璃主体Al-O网络中非桥氧减少, 聚合度提高。实验测试了玻璃的吸收光谱和荧光光谱, 并运用Judd-Ofelt理论计算Nd³⁺离子⁴F_3/2→⁴I_11/2跃迁的J-O参数Ω, 自发辐射几率A_rad, 荧光分支比β, 受激发射截面σ_e, 辐射寿命τ_rad等。结果显示: 随着SiO₂浓度的增加, 钕离子周围环境结构对称性提高, 荧光发射峰半高宽变窄, 同时受激发射截面逐渐增大。研究结果表明含有低浓度SiO₂的掺钕钙铝酸盐激光玻璃有望用于超短脉冲激光领域。