共查询到20条相似文献,搜索用时 10 毫秒
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JIA Ruo-kun JIAN Wen-ping GUO Wei SHAN Gui-ye U Qian LIU Zhao-yue BAI Yu-Bai LI Tie-jin KONG Xiang-gu 《高等学校化学研究》2004,20(6)
Erbium, Ytterbium-codoped ZrO2 nanoparticles(ZrO2∶Er3 ,Yb3 ) were prepared by the sol-emulsion-gel technique. The purpose of the present study is the application of upconversion phosphor in the biological label. In order to make out the mechanism of upconversion under 980 nm excitation the 488 nm pump was used. The influence of temperature on the crystallite phase was studied. The results confirm the upconverted mechanism in ZrO2∶Er3 ,Yb3 nanocrystals is due to an energy transfer upconversion(ETU). 相似文献
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Zhang X Yang P Li C Wang D Xu J Gai S Lin J 《Chemical communications (Cambridge, England)》2011,47(44):12143-12145
Well defined, pure hexagonal-phased NaYF(4):Yb(3+),Er(3+)/Tm(3+) microtubes and microrods were first prepared by a facile and mass production molten salt method without using any surfactant, which offers a new alternative in synthesizing such materials and opens the possibility to meet the increasing commercial demand. 相似文献
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稀土掺杂微/纳材料的偏振上转换发光在单颗粒示踪和生物医学等领域具有广泛的应用前景. 稀土离子的偏振上转换发光主要取决于其局域态的电子结构和激发态动力学. 利用单颗粒偏振上转换光学测试平台对β-NaYF4:Yb3+/ Er3+微米棒的偏振上转换发光进行了系统研究. 随发射偏振角的变化, 单个微米棒的上转换发光强度发生周期性改变, 且来自Er3+同一光谱支项的不同晶体场子能级跃迁的偏振方向不同. 与光谱支项整体的上转换发光相比, 其晶体场子能级上转换发光表现出更大的发射偏振度. 利用Er3+高度偏振的晶体场跃迁谱线, 实现了对单个微米棒空间取向的动态分析, 揭示了NaYF4:Yb3+/Er3+微米棒作为偏振各向异性的上转换荧光探针在单颗粒取向示踪方面的潜在应用. 相似文献
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《Journal of Inorganic and Nuclear Chemistry》1981,43(2):303-304
Complexes of Alizarin complexone with Sc3+, Y3+, La3+, Gd3+, Ce2+ and Yb3+ have been synthesized and characterized by, pH titrations, conductance measurements, UV, visible and IR spectral studies. 相似文献
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双掺Er3+,Yb3+离子KY(WO4)2晶体的光谱性质 总被引:9,自引:5,他引:9
研究分析了用助熔剂法生长的Er^3 /Yb^3 :KY(WO4)2晶体在室温下的吸收光谱和发射光谱,在吸收谱的350-1750nm区域,除了900-1050nm的谱带是Er^3 ,Yb^3 的共同谱带,其他的都属于Er^3 的谱带,用266nm激发时产生540-560,660-680,850-870,1450-1600nm四个发射带,用976nm激发时产生的主要是Er^3 的1450-1600nm发射带,这两 的能量转移机制不相同。 相似文献
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Dr. Rintaro Takahashi Sakiko Matsumoto Dr. Shota Fujii Dr. Theyencheri Narayanan Prof. Kazuo Sakurai 《Angewandte Chemie (International ed. in English)》2017,56(24):6734-6738
Calix[4]arene-derived surfactants form monodisperse micelles with a well-defined aggregation number (Nagg) of 4, 6, 8, 12, or 20, corresponding to the Platonic solids. This feature is in strong contrast to conventional micelles. In this study, a transition from a dodecamer (Nagg=12) to an icosamer (Nagg=20) was induced by a rapid increase in the NaCl concentration (CNaCl) using a stopped-flow device and directly observed by time-resolved small-angle X-ray scattering. The Nagg remained unchanged during the first 60 s after the increase in CNaCl , and then abruptly increased to 20. This feature resembles phase transitions in supersaturated or supercooled states, or highly cooperative phenomena. We surmise that this finding may be due to the fact that only a few Nagg values are thermodynamically allowed when Nagg is sufficiently small. This is the first observation of such an induction time in micellar aggregation. 相似文献
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Shanta Singh N Ningthoujam RS Phaomei G Singh SD Vinu A Vatsa RK 《Dalton transactions (Cambridge, England : 2003)》2012,41(15):4404-4412
GdVO(4)?:?Ln(3+) (Ln(3+) = Dy(3+), Eu(3+), Sm(3+), Tm(3+)) nanoparticles are prepared by a simple chemical route at 140 °C. The crystallite size can be tuned by varying the pH of the reaction medium. Interestingly, the crystallite size is found to increase significantly when pH increases from 6 to 12. This is related to slower nucleation of the GdVO(4) formation with increase of VO(4)(3-) present in solution. The luminescence study shows an efficient energy transfer from vanadate absorption of GdVO(4) to Ln(3+) and thereby enhanced emissions are obtained. A possible reaction mechanism at different pH values is suggested in this study. As-prepared samples are well dispersed in ethanol, methanol and water, and can be incorporated into polymer films. Luminescence and its decay lifetime studies confirm the decrease in non-radiative transition probability with the increase of heat treatment temperature. Re-dispersed particles will be useful in potential applications of life science and the film will be useful in display devices. 相似文献
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Structural Chemistry - 相似文献
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采用水热合成技术成功制备了一种新型的上转换发光纳米晶体NaGd(MoO4)2:Yb3+,Er3+.采用X射线粉末衍射分析、透射电镜和光谱分析对不同条件下所得样品的结构和发光性能进行了表征.NaGd(MoO4)2:Yb3+,Er3+和NaGd(MoO4)2具有相同的晶体结构,属于四方晶系;透射电镜观察表明,所得晶体为直径约为20 nm的纳米棒;在980 nm红外激光器的激发下,观察到了3个明显的上转换发射峰,发光中心分别位于531,552和656 nm,分别对应于Er3+2H11/2→I15/2,4S3/2→I15/2和4F9/2→4I15/2的跃迁. 相似文献
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用微乳液法合成出SiO2包覆的Yb3+,Er3+离子舣掺杂的Gd2O3粉体,X射线衍射结果表明所制备粉体为立方Gd2O3结构.透射电镜照片显示其颗粒形状近似为球形,粒径为10~40 nm;该粉体在波长为980 nm的半导体激光器激发下发射出中心波长为562 nm的绿色和660 m的红色上转换荧光,分别对应于Er3+离子的4S3/2/2H11/2→4I15/2跃迁和4F9/2→4I15/2跃迁.发光强度和激发功率关系的研究揭示其均为双光子过程,能量传递和激发态吸收是上转换发光的主要机制.由于其具有高效的上转换发光性能,而经过纳米复合后制成的纳米Gd2O3(核)/SiO2(壳),容易溶于水并易于和有机物结合,能与生物分子结合. 相似文献
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Hong-Ru Wang Victor Litvinov Wei Yu Kar Wee Eddie Peh Qian-Li Yu Yong-Feng Men 《高分子科学》2023,(12):1902-1911
The microstructural evolution of a thermoplastic polyurethane(TPU) with low hard segment content has been monitored utilizing in situ real-time synchrotron small angle X-ray scattering(SAXS) and time-domain nuclear magnetic resonance(NMR) measurements. The TPU is composed of 23 wt% of [4,4-methylenediphenyl diisocyanate(MDI)]-[1,4-butanediol(BD)] chain segments, which form hard domains, as[polytetrahydrofuran(PTHF)] forming soft domains. The number and distribution of monomer units in hard block... 相似文献
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Frederic Poineau Erik V. Johnstone Alfred P. Sattelberger Kenneth R. Czerwinski 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):235-239
Technetium tetrachloride and β-TcCl3, synthesized from the reaction of Tc metal and Cl2(g) in sealed tubes, were characterized by X-ray absorption fine structure spectroscopy. Extended X-ray absorption fine structure (EXAFS) spectroscopy measurements are in good agreement with the X-ray diffraction structures of the two compounds. For TcCl4, the absorbing Tc atom is surrounded by Cl atoms at 2.34(2) Å and Tc atoms at 3.66(4) Å. For β-TcCl3, the absorbing Tc atom is surrounded by Cl atoms at 2.40(2) Å and Tc atoms at 2.81(3), 3.66(4) and 5.71(6) Å. EXAFS spectroscopy indicates that the TcCl4 and β-TcCl3 samples obtained by sealed tube reactions are single phase. The X-ray absorption near edge structure spectra of TcCl4 and β-TcCl3 were recorded; the positions of the Tc K-edges of β-TcCl3 (21,050.5 eV) and TcCl4 (21,053.0 eV) are compared to the ones measured for α-TcCl3 (21,051.0 eV) and TcCl2 (21,048.8 eV). A correlation between the positions of the Tc K-edges and the oxidation state of the Tc atom in technetium binary chlorides was determined. 相似文献
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Y. Y. He X. L. Liu B. S. Cao Z. Q. Feng B. Dong 《Journal of Sol-Gel Science and Technology》2013,66(2):312-316
In this paper, we report a general approach to enhance the upconversion (UC) luminescence of Er3+ doped oxides phosphors by Yb3+–MoO4 2? dimer sensitizing, which induced strong green UC emissions under the 976 nm laser diode excitation. By codoping of Yb3+ and Mo6+ in the Er3+ doped TiO2 and ZnO, the green UC emissions intensity can be selectively increased about 10 and 500 times than those of Er3+–Yb3+ codoped TiO2 and ZnO, respectively. The high excited state energy transfer between |2F7/2, 3T2> state of Yb3+–MoO4 2? dimer and 4F7/2 level of Er3+ significantly avoids the nonradiative decay processes happened at lower energy levels of Er3+, and then increases the green UC emissions efficiently. The proposed Yb3+–MoO4 2? dimer sensitizing has been realized as an efficient way to enhance the green UC emissions in other Er3+ doped oxides phosphors. It is expected that the selective enhanced green UC emissions sensitized by Yb3+–MoO4 2? dimer in Er3+ doped oxides phosphors can greatly extend their scope of applications. 相似文献
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Introduction The cyano branched carbohydrates are useful, versatil intermediaries for the synthesis of branched sugars having biological activity in nature. Owing to the good yield, mild reaction conditions and high stereospecificity, the phase transition catalysis(PTC)method has been widely used to the syntheses of C- 相似文献
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Ambapuram Meenakshamma Parnapalli Muni Mounika Dr. Maddala Gurulakshmi Dr. Kalvapalli Susmitha Prof. D. Haranath Lalit Goswami Prof. Govind Gupta Dr. Pola Someshwar Dr. Mitty Raghavender 《Chemphyschem》2023,24(22):e202300572
Giant power conversion efficiency is achieved by using bifunction ZrO2 : Er3+/Yb3+assisted co-sensitised dye-sensitized solar cells. The evolution of the crystalline structure and its microstructure are examined by X-ray diffraction, scanning electron microscopy studies. The bi-functional behaviour of ZrO2 : Er3+/Yb3+ as upconversion, light scattering is confirmed by emission and diffused reflectance studies. The bi-function ZrO2 : Er3+/Yb3+ (pH=3) assisted photoanode is co-sensitized by use of N719 dye, squaraine SPSQ2 dye and is sandwiched with Platinum based counter electrode. The fabricated DSSC exhibited a giant power conversion efficiency of 12.35 % with VOC of 0.71 V, JSC of 27.06 mA/cm2, FF of 0.63. The results, which motivated the development of a small DSSC module, gave 6.21 % and is used to drive a tiny electronic motor in indoor and outdoor lighting conditions. Small-area DSSCs connected in series have found that a VOC of 4.52 V is sufficient to power up Internet of Things (IoT) devices. 相似文献
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Dr. Kyung Hwan Kim Hosung Ki Key Young Oang Prof. Shunsuke Nozawa Dr. Tokushi Sato Prof. Joonghan Kim Prof. Tae Kyu Kim Prof. Jeongho Kim Prof. Shin-ichi Adachi Prof. Hyotcherl Ihee 《Chemphyschem》2013,14(16):3687-3697
The mechanism of a photochemical reaction involves the formation and dissociation of various short-lived species on ultrafast timescales and therefore its characterization requires detailed structural information on the transient species. By making use of a structurally sensitive X-ray probe, time-resolved X-ray liquidography (TRXL) can directly elucidate the structures of reacting molecules in the solution phase and thus determine the comprehensive reaction mechanism with high accuracy. In this work, by performing TRXL measurements at two different wavelengths (400 and 267 nm), the reaction mechanism of I3− photolysis, which changes subtly depending on the excitation wavelength, is elucidated. Upon 400 nm photoexcitation, the I3− ion dissociates into I2− and I. By contrast, upon 267 nm photoexcitation, the I3− ion undergoes both two-body dissociation (I2−+I) and three-body dissociation (I−+2I) with 7:3 molar ratio. At both excitation wavelengths, all the transient species ultimately disappear in 80 ns by recombining to form the I3− ion nongeminately. In addition to the reaction dynamics of solute species, the results reveal the transient structure of the solute/solvent cage and the changes in solvent density and temperature as a function of time. 相似文献
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Hong Ha Thi Vu Timur Sh. Atabaev Nang Dinh Nguyen Yoon-Hwae Hwang Hyung-Kook Kim 《Journal of Sol-Gel Science and Technology》2014,71(3):391-395
Bifunctional magneto-optical nanocomposites with Fe3O4 nanoparticles as a core and erbium and lithium codoped gadolinium (Gd2O3:Er3+, Li+) as the shell were synthesized successfully using a simple urea homogeneous precipitation method. The fabricated Fe3O4@Gd2O3:Er3+, Li+ particles were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence spectroscopy and quantum design vibrating sample magnetometry. The upconversion emission intensity was enhanced significantly comparing to that without Li+ ions. These bifunctional composites are expected to be potentially applied for drug delivery, cell separation and bioimaging. 相似文献