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1.
Enhanced mid-IR luminescence of Tm3+ ions in Ga2S3 nanocrystals embedded chalcohalide glass ceramics
Shixun Dai Changgui Lin Feifei Chen Xianghua Zhang Chao Liu Kai Xu Jong Heo Xiang Shen Xunsi Wang 《Journal of Non》2011,357(11-13):2302-2305
Chalcohalide glass with a composition of 65GeS2–25Ga2S3–10CsI (in mol%) doped with 0.6 wt% Tm3+ ions was prepared by conventional melt–quench method. By heat treating the precursor glass at 20 °C above its glass transition temperature Tg for different durations, IR transparent glass ceramics were obtained. X-ray diffraction (XRD) and scanning electron microscope (SEM) showed that Ga2S3 crystallites were precipitated after heat treatment and their grain sizes were in nano-scale and increased with the elongation of heat treated time. Mid-IR luminescence properties of the glass and transparent glass ceramic samples were investigated. The emissions at 2.3 and 3.8 μm corresponding to optical transitions of 3H4 → 3H5 and 3H5 → 3F4 of Tm3+ ions were significantly enhanced by the presence of Ga2S3 nanocrystals and reached a maximum after 8 hours treatment. 相似文献
2.
《Journal of Non》2006,352(28-29):2969-2976
A colorless transparent luminescence material was successfully prepared by impregnation of leached, porous glass with Tb3+ ions followed by reductive sintering in a CO atmosphere. Tb3+ emissions under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation clearly showed the most intense emission band to be situated at 543 nm, which corresponds to the 5D4 → 7F5 transition. Sintering of the Tb glass in a reducing atmosphere resulted in a significant enhancement of Tb3+ emission intensity in comparison with sintering in air. The presence of traces of cerium ions was verified in Tb glasses, and more Ce3+ ions were produced as a result of the reductive sintering. The increase in Ce3+ ions was believed to be mainly responsible for the enhancement of 5D3 → 7Fj and 5D4 → 7Fj transitions from Tb3+ ions owing to an energy transfer channel. A clearly defined difference in the spectral energy distribution of Tb3+ emissions was found for 231 nm UV and 160 nm VUV excitation of the Tb glass. The phenomenon of cross relaxation was only observed under 231 nm UV excitation. Different excitation mechanisms were taken into account. Direct excitation of Tb3+ ions together with Ce3+ ions occurred in the Tb glass under the 231 nm UV light, whereas indirect excitation consisting of host absorption of energy and transfer from host to Tb3+ ions occurred under the 160 nm VUV light. 相似文献
3.
《Journal of Non》2007,353(24-25):2431-2435
Y3+(La3+), Eu3+ and Bi3+ ions co-doped sol–gel silica glasses were synthesized. Photoluminescence spectra show that there is energy transfer from Bi3+ ions to the emission band of Eu3+ ions. The co-dopants Y3+ or La3+ have strong effects on the local structure and luminescence of Eu3+ ions. For 0.5 mol% Eu3+ ions doped glasses, the co-doping of 1 mol% Bi3+ and 1 mol% Y3+ is the most appropriate for the sensitization from Bi3+ to Eu3+. The sensitization effectiveness from Bi3+ ions to Eu3+ ions was studied by changing the amount of Bi3+ and Y3+, and clusters containing rare earth ions and Bi3+ ions dominate the energy transfer processes. The comparison of luminescent R-values (the intensity ratio of 5D0 → 7F2/5D0 → 7F1 in Eu3+ ions) between glasses containing La3+ and containing Y3+ verifies the formation of clusters in sol–gel glasses. As a favorable configuration for energy transfer, the accurate design and synthesis of clusters-contained glasses may provide a new kind of luminescent materials. 相似文献
4.
In the present work, Ce3+/Tb3+ co-doped 60P2O5-30BaO-10B2O3 phosphate glasses are prepared and their luminescence properties are presented. Under excitation at 303 nm, the Ce3+ ions singly doped sample show a novel red emission besides the UV one. The co-doped samples show enhanced Tb3+ ions emission with the increasing of Tb3+ ions concentration at the cost of Ce3+ emission. The mechanism of this luminescent behavior is discussed with respect to the relevant energy transfer process. 相似文献
5.
Nanoparticles of tungsten trioxide, WO3, are used to enhance the luminescence emission intensity of terbium(III) ions embedded in a silica matrix. Optically active components have been incorporated into silica xerogel by impregnation of silica xerogel immersed firstly in WO3 sol and subsequently in a solution with Tb(III). Photoluminescence studies make it possible to describe a plausible mechanism of the Tb(III) enhanced luminescence that could be attributed to energy transfer via excited WO3 nanoparticles to Tb(III) ions in the system: Tb(III) ions–WO3 nanocrystals–SiO2. The effect related to WO3 nanoparticles of various sizes influences not only changes in the emission intensity and band shifting of WO3 nanostructures but also the same spectral parameters of the emitting Tb(III) ions. 相似文献
6.
Tb3+ doped transparent oxyfluoride glass ceramics containing BaGdF5 nanocrystals were prepared. The transmission spectra, photoluminescence spectra, decay time and X-ray excited luminescence spectra of the Tb3+-doped glass and glass ceramics were investigated. Energy transfer from Gd3+ to Tb3+ has been observed in the glass and glass ceramics. The emission intensity of green band (5D4 → 7FJ) of the Tb3+-doped glass ceramics is enhanced compared with that of the glass under ultraviolet and X-rays, which could be attributed to that the generation of BaGdF5 nanocrystals with low phonon energy reduces the non-radiative transitions. 相似文献
7.
A.S. Gouveia-Neto L.A. Bueno A.C.M. Afonso J.F. Nascimento E.B. Costa Y. Messaddeq S.J.L. Ribeiro 《Journal of Non》2008,354(2-9):509-514
Energy-transfer excited upconversion luminescence in Ho3+/Yb3+- and Tb3+/Yb3+-codoped PbGeO3–PbF2–CdF2 glass and glass–ceramic under infrared excitation is investigated. In Ho3+/Yb3+-codoped samples, green (545 nm), red (652 nm), and near-infrared (754 nm) upconversion emission corresponding to the 5S2(5F4) → 5I8, 5F5 → 5I8, and 5S2(5F4) → 5I7 transitions, respectively, was observed. Blue (490 nm) emission assigned to the 5F2,3 → 5I8 transition was also detected. In the Tb3+/Yb3+-codoped system, bright UV–visible emission around 384, 415, 438, 473–490, 545, 587, and 623 nm, identified as due to the 5D3(5G6) → 7FJ(J = 6, 5, 4) and 5D4 → 7FJ(J = 6, 5, 4, 3) transitions, was measured. The comparison of the upconversion process in glass ceramic and its glassy precursor revealed that the former samples present much higher upconversion efficiencies. The dependence of the upconversion emission upon pump power, and doping contents was also examined. The results indicated that successive energy-transfer between ytterbium and holmium ions and cooperative energy-transfer between ytterbium and terbium ions followed by excited-state absorption are the dominant upconversion excitation mechanisms herein involved. The viability of using the samples for three-dimensional solid-state color displays is also discussed. 相似文献
8.
Low-density silica xerogels were formed into spherical pellets using a process in which a xerogel suspension containing sodium alginate was solidified through free fall in a solution of divalent ions that induce the droplet solidification. Pellet preparation was also carried out at laboratory scale by using a syringe instead of the material-consuming unit used for scaling up. When beads are made from a suspension of dried-and-calcined xerogel material, the textural properties such as porosity and surface area are significantly altered. Both properties are reduced by 30-50% compared to the starting reference material. Properties were improved when a suspension of dried xerogel that is less sensitive to contact with water was used: specific surface area was maintained at its initial level and porosity decreased by 25%. 相似文献
9.
S. Kvapil Jirí Kvapil B. Mnek B. Perner B. K. Sevastyanov V. P. Orekhova 《Crystal Research and Technology》1982,17(2):225-229
YAG crystals doped with 0.01 wt% Cr were grown by Czochralski method using 98% Ar + 2% H2 protective atmosphere. Four colour varieties of the crystals were prepared in the dependence of the Al2O3 :Y2O3 ratio in the melt and the sign of electrical potential above the melt level. New absorption bands were attributed to the O− centre (400 to 480 nm), F centre (357, 500, and 833 nm) or Cr3+ at another site than octahedral (455, and 612 nm). 相似文献
10.
Two-component material consisting of terbium(III) ions doping silica xerogel prepared by sol–gel procedure shows enhanced Tb(III) photoluminescence. We postulate that in this material the enhancement is owing to energy transfer from one of the defect states in silica to emitting states 3D3 and 5D4 of Tb(III).Surface plasmon resonance effect causes two contrary phenomena. Thus, if in the vicinity of the Tb(III) emission centers are present nanoparticles of Ag, observed is additional improvement of the Tb(III) emission. While, presence of Au nanostructures in the silica doped with Tb(III) causes quenching of the luminescence. In general, both the three-component materials exhibit enhancement of the component silica emission band in the resultant 380 nm band and relatively high thermal stability, especially above 600 °C. 相似文献
11.
利用水热法成功合成了近红外量子剪裁荧光粉LuBO3∶15;Tb3+,x; Yb3+(x=0,1,2,4,8,12).通过X射线衍射(XRD)、光致发光谱(PL)、激发谱(PLE)和荧光寿命测试了合成物质的物相结构与发光性质.在286 nm(Tb3+∶7 F6→5D)紫外光激发下,观察到了Tb3∶5D4→7Fj(J=6,5,4,3)可见波段特征发射光和Yb3+:2F5/2→2F7/2的近红外光.研究了Yb3+浓度与激发发射光谱和荧光寿命之间的关系,表明Tb3+和Yb3+之间存在能量传递.当Tb3和Yb3+掺杂摩尔浓度分别为15;和2;时,近红外发射最强.计算得知,其最大下转换量子效率为160.74;. 相似文献
12.
Heqing Yang Banglao Zhang Xiaoguang Wang Xingjun Wang Tie Li Songhai Xie Xi Yao 《Journal of Crystal Growth》2005,280(3-4):521-529
III–V semiconductor Indium Arsenide (InAs) nanocrystals embedded in silica glasses was synthesized by combining the sol–gel process and heat treatment in H2 gas. The size of InAs nanocrystals can be easily controlled via changing the In and As content in the starting materials and the heating temperature in a H2 gas atmosphere. Absorption measurements indicate a blue shift in energy with a reduction on the In and As content in the SiO2 gel glasses as a result of quantum confinement effects. A near-infrared photoluminescence with peak at 3.40 μm was observed at 6 K under 514.5 nm Ar+ laser excitation from InAs nanocrystals embedded in the silica gel glasses. 相似文献
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14.
采用高温固相法合成了LiCaPO4∶Tb3+绿色荧光粉,并研究了材料的发光性质。LiCaPO4∶Tb3+材料呈多峰发射,发射峰位于437 nm、491 nm、545 nm、587 nm和625 nm,分别对应Tb3+的5D3→7F4和5D4→7FJ=6,5,4,3跃迁发射,主峰为545 nm;监测545 nm发射峰,所得激发光谱由4f75d1宽带吸收(200~330 nm)和4f-4f电子吸收(330~400nm)组成,主峰为380 nm。研究了Tb3+掺杂浓度,电荷补偿剂Li+、Na+、K+和Cl-及敏化剂Ce3+对LiCaPO4∶Tb3+材料发射强度的影响,发现调节激活剂浓度、添加电荷补偿剂或敏化剂均可提高材料的发射强度。 相似文献
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16.
The luminescence of silica glass, prepared by plasma chemical vapor deposition (PCVD) and quartz glass of type IV (trade mark KS-4V) methods, were studied while irradiated with pulses of ArF laser (193 nm) light in the range of sample temperatures between 10 and 300 K. The samples contain less than 0.1 ppm metallic and hydroxyl impurities. The samples synthesized by PCVD were of two kinds. The first one (amorphous) was as-deposited from plasma at a substrate tube temperature of ~1200 °C. The second one (fused) was prepared from the first by the tube collapsing with an external burner. In this process, a section of the substrate tube with the deposited glass was installed in a lathe and processed at a temperature of ~2100 °C during ~20 min until the tube was transformed to a rod. After such processing, the rod was cooled down to room temperature in air at an average rate of about 400 °C per min. The only observed luminescence possesses two broad bands, with not well defined position, one at 2.6–2.9 eV (a blue band) and another in the range of 4.4 eV (an UV band). There is a correspondence in luminescence properties between KS-4V silica and fused PCVD silica. Those bands have been attributed to oxygen deficient centers (ODC). No luminescence is observed in amorphous PCVD silica under irradiation with 193 nm laser light. So, formation of the sample by melting at least stimulates formation of ODCs at 193 nm. The blue band decays obeys to power law ~t?1 and is detected in the range of time 10 ns to 300 μs. The UV band possesses a fast, practically repeating excitation pulse, and a slow component (~30 μs). The obtained new kinetics data are compared with known in literature for lone twofold-coordinated silicon having exponential decay for the blue band equal to 10 ms and 4.5 ns for the UV band. That shows the blue band of new studied samples under ArF laser possesses decay component faster and the UV band slower than that of the twofold-coordinated silicon center. This corresponds to the recombination process of luminescence excitation by laser. We propose a model of the processes as charge separation under excitation with creation of a nearest self-trapped hole and electron trapped on the twofold-coordinated silicon, modified by its surrounding atoms or ions. This pair is recombining then with luminescence. 相似文献
17.
本文用共沉淀法制备了纳米晶ZrO2:Tb3+荧光粉,并对它的晶体结构、颗粒大小和光致发光性质进行了表征.XRD测试结果表明:以此工艺制备的纳米晶ZrO2:Tb3+含有单斜相和四方相两种微观结构,四方相所占比例随着Tb3+离子浓度的提高而提高,Tb3+离子的掺入有稳定ZrO2四方晶相的作用.纳米晶ZrO2:Tb3+粉体中Tb3+的强室温特征发射的两个主发射带为5D3→7F1和5D4→7F1的跃迁.荧光强度与Tb3+浓度的关系研究表明:5D3和5D4能级有不同的猝灭规律,由于(5D3,7F6)→(5D4,7Fo)的交叉弛豫,使得5D3→7F5跃迁的猝灭浓度较低,在我们的实验中,掺1.5;摩尔分数Tb3+时5D3→7F1跃迁发射最强,掺6;摩尔分数Tb3+时5D4→7F1跃迁发射最强. 相似文献
18.
Transparent SiO2:Li2O:Nb2O5 glass doped with Tm3+ has been prepared by the sol–gel method, and heat-treated in air (HT) at temperatures between 500 and 800 °C. X-ray diffraction (XRD) patterns and Raman spectroscopy show SiO2 and LiNbO3 phases in samples HT above 650 °C, and a NbTmO4 phase for T > 750 °C. The XRD SEM analysis show increasing particle size and number with the increase of HT temperature. Intra-4f12 transitions due to Tm3+ ion dispersed in the matrix are observed in samples with T > 650 °C. The luminescence is dominated by the 1G4 → 3F4 (~650 nm), 1D2 → 3F3 (~780 nm), 3H4 → 3H6 (~800 nm), 3H5 → 3H6 (~1200 nm) and 3H4 → 3F4 (~1500 nm) transitions under resonant excitation to the ion levels. 相似文献
19.
两相有序共晶材料由于具有不同折射率的两晶相呈现有序排列,可降低荧光在共晶材料内部的散射而实现导光功能,可被应用于高分辨探测成像器件中。本工作根据定向凝固原理,用微下降法生长技术制备得到了直径为3 mm的GdAlO3∶Tb3+-Al2O3两相有序共晶。通过SEM和元素分析,探究了GdAlO3∶Tb3+-Al2O3共晶内部的微结构,结果显示,所得共晶中GdAlO3∶Tb3+晶相均匀有序地分布于基质Al2O3晶相中,GdAlO3∶Tb3+晶相直径的大小受生长速率的影响,速率越快,直径越小。所制备得到的GdAlO3∶Tb3+-Al2O3有序共晶在X射线辐照下发射出明亮的绿色荧光,并在GdAlO3∶Tb3+晶相中定向传播,有望被用作X射线探测成像材料,提高探测器的空间分辨率。 相似文献
20.
《Journal of Crystal Growth》2006,286(2):487-493
The pure hexagonal phase YBO3:Tb3+ phosphors with good crystallinity and uniform size were prepared by hydrothermal reaction (HR). The particle size and morphology can be well controlled by adjusting the concentration of ammonium acetate and varying the reaction temperature and time. The phosphor prepared by HR emits an intense green light at 543 nm, which is stronger than that from crystals synthesized by solid-state reaction (SR). The influence of Tb3+-doping concentration on the crystallization and luminescent properties were investigated. The results showed that the samples exhibited a higher quenching concentration of Tb3+ in comparison with those prepared by the SR. The phenomena were also discussed. 相似文献