PbO对Tm3+/Ho3+/Yb3+共掺碲酸盐玻璃三基色上转换发光的影响

用高温熔融法制备了Tm3+/Ho3+/Yb3+共掺碲酸盐玻璃,在TeO2-ZnO-La2O3玻璃组分的基础上,引入声子能量较低的PbO,研究了PbO对基质样品拉曼光谱以及Tm3+/Ho3+/Yb3+共掺样品上转换发光光谱的影响.结果表明,随着PbO含量的增加,样品的最大声子能量下降比较明显,同时样品的声子态密度也有减小趋势;在975nm波长激光二极管(LD)激励下,随着PbO含量的增加,Tm3+/Ho3+/Yb3+共掺样品上转换蓝光(480nm)、绿光(546nm)和红光(662nm)的发光强度都有明显增强,且PbO的引入对上转换蓝光发光强度的影响要大于其对绿光和红光的影响.     

掺铒氧氟碲酸盐玻璃的上转换发光研究

研究了掺铒氧氟碲酸盐玻璃的吸收光谱和上转换发光光谱，分析了Er^3 离子在氧氟碲酸盐玻璃中的上转换发光机理．结果表明：通过975nm的激光二极管(LD)激发，在室温下同时观察到强烈的绿光(524和545nm)和红光(655nm)，分别是由于Er^3 离子^2H11／2→I15／2，^4S3／2→I15／2，和^4F9/2→I15／2跃迁．随PbF2含量增加，绿光的发光强度增加趋势较小，而红光的发光强度增加趋势大于绿光．上转换发光机理主要涉及能量转移和激发态吸收，强烈的绿光和红光激发都是由于双光子吸收过程．     

掺铒TeO2-Nb2O5-ZnO系统玻璃的上转换发光性能

稀土离子掺杂碲酸盐系统玻璃是一类应用前景良好的上转换发光材料.研究了含铒TeO2-Nb2O5-ZnO系统玻璃在980nm抽运下的上转换光谱,结果发现存在3个上转换荧光谱带,分别对应于2H11/2→4I15/2、4S3/2→4I15/2和4F9/2→4I15/2,而且Er3 含量的增加可明显提高材料在530、550和660nm附近的发光性能.少量的ZnO引入既可以大幅提升材料的上转换发光强度,又能保持铌碲酸盐玻璃良好的化学稳定性.材料的发光机制主要是激发态吸收(ESA)和能量转移(ET),最大声子能量的降低是上转换发光增强的主要原因.     

碱金属和碱土金属对掺Tm3+碲酸盐玻璃光谱性质的影响

研究了碱金属和碱土金属离子修饰的掺铥碲酸盐玻璃的光谱性质,讨论了碱金属和碱土金属对掺铥碲酸盐玻璃J-O强度参数、1.46μm荧光发射强度、荧光半高宽、受激发射截面等光谱性质的影响,并与一些传统氧化物玻璃进行了比较.研究表明碱金属Li 和碱土金属Ba2 掺碲酸盐玻璃更适宜用作掺铥光放大器基质.含Li 的碲酸盐玻璃展现出7.90×10-21cm2的高发射截面;含Ba2 碲酸盐玻璃具有7.55×10-21cm2的高发射截面、103nm的荧光半高宽.     

镱离子敏化与温度对铒离子掺杂碲酸盐玻璃上转换光谱的影响

用熔融-淬冷法制备了玻璃样品系列75TeO₂-20ZnO-(4.6-x)La₂O₃-0.4Er₂O_3-xYb₂O₃ (x=0, 0.4, 0.8, 2.0, 3.2, 4.0), 研究了镱离子的掺入及温度的变化对该玻璃系统上转化光谱的影响, 结果表明: 在常温下, 当Yb³⁺离子浓度达到2mol%时, 上转换红光和545nm绿光都达到了最大值, 此时545nm绿光强度是未掺Yb³⁺时的6倍左右, 红光强度为未掺Yb³⁺时的4倍左右; 当温度在8～300K变化时, 530nm绿光强度随着温度的升高而增大, 545nm绿光与657nm红光强度随着温度的升高首先增大, 在80K达到最大值, 然后随着温度的升高而下降. 通过速率方程, 分析了镱离子的敏化及温度对该玻璃系统上转换光谱的影响.     

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。     

上转换亚碲酸盐光纤激光器研究进展

亚碲酸盐玻璃由于具有较低的声子能量,加上其优良的化学稳定性、热稳定性和机械强度及其光学性能,其可作为光纤放大器和上转换光纤激光器的较理想的基质材料。文章介绍了上转换激光器的主要原理,并回顾了亚碲酸盐玻璃上转换激光器的研究进展。     

NaYF_4∶Yb,Er/Tm上转换发光强度的影响因素

含有稀土离子的上转换发光材料因具有巨大的应用价值而受到人们的广泛研究,特别是六方相NaYF4已被公认为是迄今为止发光强度最大的上转换基质材料.以稀土离子Yb和Er或Yb和Tm的共掺杂NaYF4上转换材料为研究对象,讨论了几种不同因素对其上转换发光强度的影响,并对这种上转换材料的应用与研究前景提出了几点建议.     

Er3+单掺与Er3+/Yb3+共掺Y2SiO5的上转换发光

报道了一种新的上转换发光材料X2型Y2SiO5:Er, Yb并研究了Yb3 浓度和泵浦功率对样品的上转换发光特性的影响:(1)随着Yb3 浓度的增加,绿、红光发射均呈先增强后减弱的变化,但相对于绿光发射,红光发射受Yb3 浓度的影响更剧烈,并且当12%(摩尔分数)Yb3 时,可以得到很纯的红光发射;(2)上转换发光强度与泵浦功率的关系表明,双光子吸收贡献样品的上转换发射.此外,讨论了可能的上转换机制.认为随着Yb3 浓度增加,Er3 的激发态吸收、Yb3 到Er3 的能量传递和Er3 的交叉弛豫对上转换发光的作用依次逐渐加强.     

Tm3+/Er3+/Yb3+-codoped oxyhalide tellurite glasses as materials for three-dimensional display

Blue, green and red emissions through frequency upconversion and energy transfer processes in Tm³⁺/Er³⁺/Yb³⁺-codoped oxyhalide tellurite glass under 980 nm excitation are investigated. The intense blue (476 nm), green (530 and 545 nm) and red (656 nm) emissions are simultaneously observed at room temperature. The blue (476 nm) emission was originated from the ¹G₄→³H₆ transition of Tm³⁺. The green (530 and 545 nm), and red (656 nm) upconversion luminescences were identified from the ²H_11/2→⁴I_15/2, ⁴S_3/2→⁴I_15/2, and ⁴F_9/2→⁴I_15/2 transitions of Er³⁺, respectively. The energy transfer processes and possible upconversion mechanisms are evaluated.     

Synthesis and upconversion luminescence properties of CaF2:Yb3+/Tm3+ microspheres

CaF2:Yb3+/Tm3+ microspheres were synthesized by using a simple hydrothermal method. Their structures and morphologies were characterized by X-ray diffraction (XRD) and field-effective scanning electron microscopy (FESEM). The microspheres were formed from a large number of nanospheres with almost the same diameter after annealing. The growth mechanism of the microspheres was discussed. Strong ultraviolet (UV) and blue upconversion (UC) emission from the CaF2 microspheres was observed under 980 nm excitation. The enhancement of the UV UC emission was attributed to the size effect of the nanoscale particles.     

Frequency upconversion properties of Er3+/Yb3+-codoped lead–germanium–bismuth oxide glasses

The frequency upconversion properties of Er³⁺/Yb³⁺-codoped heavy metal oxide lead–germanium–bismuth oxide glasses under 975 nm excitation are investigated. Intense green and red emission bands centered at 536, 556 and 672 nm, corresponding to the ²H_11/2 → ⁴I_15/2, ⁴S_3/2 → ⁴I_15/2 and ⁴F_9/2 → ⁴I_15/2 transitions of Er³⁺, respectively, were simultaneously observed at room temperature. The influences of PbO on upconversion intensity for the green (536 and 556 nm) and red (672 nm) emissions were compared and discussed. The optimized rare earth doping ratio of Er³⁺ and Yb³⁺ is 1:5 for these glasses, which results in the stronger upconversion fluorescence intensities. The dependence of intensities of upconversion emission on excitation power and possible upconversion mechanisms were evaluated and analyzed. The structure of glass has been investigated by means of infrared (IR) spectral analysis. The results indicate that the Er³⁺/Yb³⁺-codoped heavy metal oxide lead–germanium–bismuth oxide glasses may be a potential materials for developing upconversion fiber optic devices.     

Synthesis and upconversion luminescence of uniform beta-NaYF4:Yb3+/Tm3+ hexagonal nanoplates

Yb3+ and Tm3+-codoped hexagonal-phase NaYF4 powders were prepared by a facile hydrothermal method. The results of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) showed that the as-prepared powders were well crystallized nanoplates with high size-uniformity. Under the excitation from a 980 nm laser diode, upconversion (UC) emissions centered at approximately 291 nm (1I6 --> 3H6), approximately 346 nm (1I6 --> 3F4), approximately 361 nm (1D2 --> 3H6), approximately 451 nm (1D2 --> 3F4), approximately 474 nm (1G4 --> 3H6), approximately 644 nm (1G4 --> 3F4), and approximately 799 nm (3H4 --> 3H6) were observed in the sample. Furthermore, the intensity dependence of UC emissions on excitation power was measured. The results indicated that populating the 1I6, 1D2, 1G4, and 3H4 states were five-photon, four-photon, three-photon, and two-photon UC processes, respectively.     

Er3+/Tm3+/Yb3+共掺氟氧化物玻璃的上转换白光性质

采用高温固相法制备了Er3+/Yb3+、Tm3+/Yb3+和Er3+/Tm3+/Yb3+共掺杂的氟氧化物玻璃SiO2-Al2O3-Na2O-ZnF2,研究了980nm近红外激光激发下的上转换发光性质。研究表明,Er3+/Yb3+共掺样品呈现了上转换绿光和红光发射,Tm3+/Yb3+共掺样品呈现了强的上转换蓝光发射和弱的红光发射,Er3+/Tm3+/Yb3+三掺样品呈现了上转换白光发射。对上转换发光强度和激光功率的研究表明上转换绿光和红光发射是两光子吸收过程,上转换蓝光发射是三光子吸收过程。     

Multicolor upconversion of Er3+/Tm3+/Yb3+ doped oxyfluoride glass ceramics

Er³⁺/Tm³⁺/Yb³⁺ tridoped oxyfluoride glass ceramics was synthesized in a general way. Under 980 nm LD pumping, intense red, green and blue upconversion was obtained. And with those primary colors, multicolor luminescence was observed in oxyfluoride glass ceramics with various dopant concentrations. The red and green upconversion is consistent with ⁴F_9/2 → ⁴I_15/2 and ²H_11/2, ⁴S_3/2 → ⁴I_15/2 transition of Er³⁺ respectively. While the blue upconversion originates from ¹G₄ → ³H₆ transition of Tm³⁺. This is similar to that in Er³⁺/Yb³⁺ and/or Tm³⁺/Yb³⁺ codoped glass ceramics. However the upconversion of Tm³⁺ is enhanced by the energy transfer between Er³⁺ and Tm³⁺.     

Upconversion luminescence enhancement in Yb3+/Tm3+-codoped Lu2O3 nanocrystals induced by doping with Li+ ions

Lutetium oxide (Lu2O3) nanocrystals doped with 2%Yb3+, 0.5%Tm3+, and various doping concentrations of Li+ (0, 3, 5, 7, 10, 12, and 15 mol%) were prepared by the sol-gel method. The dependence on different doping concentrations of Li+ ions of the structure, morphology, and the upconversion emission intensity of the Lu2O3:2%Yb3+, 0.5%Tm3+ nanocrystals was investigated. The obtained Lu2O3 nanocrystals were systematically characterized by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), Fourier transformed infrared (FT-IR) spectra, Raman spectra, and upconversion spectra measurements. It was found that all the nanocrystals can be readily indexed to pure cubic phase of Lu2O3, indicating good crystallinity. The experimental results show that Li+ doping in Lu2O3:2%Yb3+, 0.5%Tm3+ nanocrystals can greatly enhance the upconversion emission intensity. The strong blue (490 nm) and the weak red (653 nm) emissions from the prepared nanocrystals were observed under 980 nm laser excitation, and attributed to the 1G4 --> 3H6 and 1G4 --> 3F4 transitions of Tm3+ ions, respectively. An simple analysis based on steady-state rate equations and a power-dependent study both indicate that the 1G4 levels can be populated by three-step energy transfer (ET) processes. The enhancement of the upconversion luminescence was suggested to be the consequence of the modification of the local field symmetry around the Tm3+ ion, reduced number of OH- groups, and the enlarged nanocrystal size induced by the Li+ ions.     

Er3+/Ho3+共掺GeS2-In2S3-CsI玻璃上转换发光和能量传递研究

用熔融急冷法制备了系列Er3+/Ho3+共掺80GeS2-10in2S3-10CsI硫卤玻璃,测试了样品的状态稳定性、拉曼光谱、吸收光谱以及上转换光谱.在该样品中出现了强烈的绿光(526、549nm)和红光(660nm),分别对应于2H11/2-4I15/2(Er3+)、4S3/2→4I15/2(Er3+)十5S2(5...