共查询到20条相似文献,搜索用时 15 毫秒
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OH− and Cl− doped Bi4Ge3O12 (BGO) single crystals had been grown by Vertical Bridgman (VB) method. The structure of these crystals was determined by XRD, the transmittance and emission spectra in near infrared region (NIR) were measured at room temperature. 5% OH− doped BGO shows a significant emission band peaking around 1181 nm under 808 nm laser diodes (LDs) excitation, and the 5% Cl− doped BGO exhibits a relatively weak emission band as well. 100% and 5% OH− doped BGO show noticeable emission band centered at about 1346 nm under 980 nm LDs excitation. 相似文献
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M. Sekita 《Journal of luminescence》1981,22(4):335-347
The emission and excitation spectra of the Bi2Ge3O9:Eu crystal are observed at 77 K and 297 K. The spectra contain groups of sharp lines which are attributed to the transitions within 4f6 (Eu3+) configuration. The numbers of Stark splitting of terminal levels of transitions from 5D0 and 7F0 multiplets indicate that Eu3+ substitutes for Bi3+ in Bi2Ge3O9. Tentative assignment of Stark levels of 7F0-4 multiplets is made to crystal quantum numbers of C3 symmetry which represents the site symmetry of Bi3+ in Bi2Ge3O9. The following set of values of crystal field parameters of the C3 point group is found to give the best overall agreement between the observed energy levels and the calculated levels: B20 = -533.84 cm-1, B40 = 1085.99 cm-1, Re(B43) = 327.57 cm-1, Im(B43) = 75.209 cm-1, B60 = 185.02 cm-1, Re(B63) = - 68.475 cm-1, Im(B63) = - 300.45 cm-1, Re(B66) = 137.24 cm-1 and Im(B66) = 882.29 cm-1. 相似文献
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The luminescence of Eu3+ and Tb3+ in Bi2Al4O9 is reported. It is shown that the Bi3+ excitation energy does not migrate through the lattice. The Cr3+ ion shows 704.5 nm line emission in this host lattice. 相似文献
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Dominik Uhlich 《Journal of luminescence》2008,128(10):1649-1654
This work reports on the phase formation during a solid-state reaction of Eu3+-doped garnets with the general formula A3B2Ge3O12 (A=Ca, Sr and B=Ga, In, Y) and their luminescent properties. It is shown by XRD and DTA/TG experiments that the garnet-phase formation is completed at 1100-1200 °C. Moreover, it turned out that the position of the oxygen to europium charge-transfer band and the intensity of the forbidden 4f-4f transitions of Eu3+ is dependent on the covalent interaction between the Eu3+ activator and the surrounding oxygen anions. The investigated red-emitting luminescent materials show high lumen equivalents and deep red emission at the same time, which makes them attractive for the application in LEDs (light emitting diodes), in particular for near UV-emitting LEDs. 相似文献
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采用高温熔融法制备了xBi2O3-50B2O3-(50-x)BaO玻璃, 测定了样品玻璃的近红外光区的发射谱、荧光寿命以及Raman光谱. 在808 nm波长光的激发下, 50Bi2O3-50B2O3二元玻璃中未观察到近红外发光; 随体系中BaO的加入, 当x为40, 45以及49时, 玻璃样品中观察到了近红外宽带发光现象; BaO含量进一步增加, 当x=10–30时, 近红外发光现象消失; 而当玻璃中Bi浓度很低时, 在0.5Bi2O3-50B2O3-50BaO及1Bi2O3-50B2O3-50BaO玻璃中发现了近红外发光现象, 且存在多个发光峰. 对铋离子近红外发光机理进行了初步的探讨. 相似文献
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Weerapong Chewpraditkul Krittiya SreebunpengMartin Nikl Jiri A. MaresKarel Nejezchleb Akapong PhunpueokChalerm Wanarak 《Radiation measurements》2012,47(1):1-5
The scintillation properties of Lu3Al5O12:Pr3+ (LuAG:Pr) single crystal grown by the Czochralski method with praseodymium concentration of 0.19 mol% were investigated. For a comparison, a good quality Bi4Ge3O12 (BGO) single crystal grown by Bridgman method was also studied. The light yield and energy resolution were measured using photomultiplier tube (XP5200B PMT) readout. Moderate light yield of 15,900 photons per MeV was measured for the LuAG:Pr(0.19%) crystal. For 662 keV gamma rays (137Cs source), an energy resolution of 6.5% obtained for LuAG:Pr(0.19%) is much better than that of 9.0% obtained for BGO. The light yield non-proportionality and energy resolution versus energy of gamma rays were measured and the intrinsic resolution of the crystals was determined after correcting the measured energy resolution for PMT statistics. The LuAG:Pr(0.19%) showed a good proportionality of the light yield within 5% over the energy range from 1274.5 keV down to 32 keV, which is much better than that of 14% for BGO. The photofraction was determined at 320 and 662 keV for both crystals and compared with the ratio of the cross-sections for the photoelectric effect to the total one calculated using WinXCOM program. 相似文献
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The effect of iron and manganese co-doping on the light-induced, dark- and photoconductivity and holographic properties of Bi4Ge3O12 crystals in comparison with Fe- and Mn-single doping is studied. Fe+Mn co-doped crystals exhibited strong photochromic effect at room temperature, the photochromic effect being fully reversible by thermal annealing. The observed light-induced absorption changes and non-linear dependence of photoconductivity on light intensities indicate deep and shallow photoactive levels contribution to the charge transport mechanism of Fe+Mn co-doped BGO. Holographic gratings are successfully recorded at different wavelengths and a possibility to extend the photorefractive sensitivity into the red spectral range is demonstrated. It is found furthermore that Fe+Mn-doping combination leads to faster response time during holographic recording, especially after a preliminary exposure with ultraviolet light, in comparison with Fe- and Mn-single doping. 相似文献
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Stearic acid coated Bi2O3 nanoparticles in the size range of 5-13 nm were synthesized by the microemulsion method. HRTEM showed that the morphology of Bi2O3 nanoparticles was ellipsoidal. The absorption edge of Bi2O3 nanoparticles showed a blue shift of ∼0.45 eV, comparing with that of the bulk Bi2O3. At room temperature, Bi2O3 nanoparticles also showed a strong luminescence at 397 and 420 nm, depending on the excitation wavelength. 相似文献
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Infrared reflection and polarized Raman scattering spectra of cubic Td6 Bi4Ge3O12 single crystals were recorded, allowing the classification of the observed phonon modes into the different allowed symmetry. There is a good agreement with group theoretical predictions, since 25 phonon modes are localized, among the expected 27 ones. An assignment in terms of the GeO4 “tetrahedra” vibrations is tentatively given and discussed. 相似文献
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研究了BGO晶体在不同温度下(在300—1323 K的温度范围)的拉曼光谱及其熔体的高温拉曼光谱,分析了BGO晶体结构随温度变化的规律及BGO熔体的结构特征.随着温度的升高,BGO晶体的拉曼光谱谱峰都不同程度地向低波数方向移动,也存在不同程度的展宽,同时强度减弱.另外,在BGO熔体中存在[GeO4]和[BiO6]的结构基团;但两种结构之间的联键消失,即在熔体中二者是相互独立的生长基元.
关键词:
高温拉曼光谱
熔体
BGO晶体 相似文献
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Tianxing Lin Jinhai Si Tao Chen Xiaoli Wang Kazuyuki Hirao 《Optics Communications》2007,275(1):230-233
The ultrafast nonlinear optical properties of Bi2O3-B2O3-SiO2 oxide glass were investigated using a femtosecond optical Kerr shutter (OKS) at wavelength of 800 nm. The nonlinear response time of this Bi2O3-doped glass was measured to be <90 fs. The nonlinear refractive-index n2 was estimated to be 1.6 × 10−14 cm2/W. Measurements for the dependence of Kerr signals on the polarization angle between the pump and probe beams showed that the Kerr signals induced by 30-fs pulse laser arose mainly from the photoinduced birefringence effect. 相似文献
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R.D. Shannon J.D. Bierlein J.L. Gillson G.A. Jones A.W. Sleight 《Journal of Physics and Chemistry of Solids》1980,41(2):117-122
Single crystals of Bi2Sn2O7 were grown in a Bi2O3 flux. Phase transitions were identified at about 90 and 680° using X-ray, SHG, DSC, dielectric, and optical data. γ-Bi2Sn2O7, which exists above 680°C is centric and cubic with a = 10.73 Å at 700°, and it probably has the ideal pyrochlore structure. β-Bi2Sn2O7, which exists between 680° and about 90°C, is acentric but remains cubic with a = 21.40 Å. α-Bi2Sn2O7, which exists from about 90°C to below room temperature, is acentric and noncubic, probably tetragonal with a = 21.328 and c = 21.545 Å. The α-β transition is first order, and the β-γ transition appears to be second order. Substitutions of Pb2+ or Cd2+ for Bi3+ and of Ga3+, Rh3+ Sc3+, In3+, Sb5+ Nb5+ or Ta5+ for Sn4+ lower the α-β transition temperature. 相似文献
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Magnetometric and neutron diffraction studies of polycrystalline NdCo2GE2, ErCo2Ge2 and PrFe2Ge2 compounds were carried out in the temperature range between 4.2 and 300 K. All samples are antiferromagnetic with Néel temperature 26.5, ~ 4.2 and 13 K, respectively. The RECo2Ge2 compounds have collinear antiferromagnetic order of +?+? type. For PrFe2Ge2 a sinusoidal magnetic structure is observed. Magnetic moment is localized on RE atoms only and is equal to that of RE3+ free ion value. In ErCo2Ge2 the magnetic moment of Er atoms is perpendicular to the c-axis, whereas for remaining compounds it is parallel to the c-axis. 相似文献
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OH− doped and Bi-rich Bi4Ge3O12 (BGO) single crystals were grown by Vertical Bridgman (VB) method. The structure of these crystals was determined by XRD, and the emission spectra in visible and near infrared region (NIR) were measured at room temperature. The emission spectrum of Bi-rich BGO has extra peaks at 385, 367 and 357 nm, Bi-rich BGO after annealing in Ar at 500 °C for 5 h shows a significant emission band peaking around 1170 nm under 808 nm laser diodes (LDs) excitation, and OH− doped BGO shows a noticeable emission band centered at about 1346 nm under 980 nm LDs excitation. A brief discussion is presented. 相似文献
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Qiuhua Nie Tiefeng Xu Xiang Shen Xudong Zhang 《Journal of Physics and Chemistry of Solids》2007,68(4):477-481
A series of Er3+-doped Bi2O3-B2O3-SiO2-Na2O glasses with different hydroxyl groups were prepared and the interaction between the Er3+ ions and OH groups was investigated. Infrared spectra were measured in order to calculate the exact content of OH groups in samples. The observed increase of the fluorescence lifetime with the oxygen bubbling time has been related to the reduction in the OH content concentration evidenced by infrared (IR) absorption spectra, which confirmed that the OH groups were dominant quenching centers of excited Er3+ and a cause of concentration quenching of 1.5 μm band emission. Various nonradiative decay rates from 4I13/2 of Er3+ with the change of OH content were determined from the fluorescence lifetimes and radiative decay rates, which were calculated on the basis of Judd-Ofelt theory. 相似文献
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The ionic conduction of sintered samples of Bi2O3?Y2O3 containing 20–30 mol% Y2O3 has been investigated by means of ac conductivity experiments and EMF measurement of an oxygen concentration cell using the specimen tablet as electrolyte. Ac conductivity was measured at a frequency of 10 kHz under oxygen partial pressures ranging from 1 to 10-21 atm. The results show that these materials possess high ionic conduction. The conductivities for samples containing 22.5–30 mol% Y2O3 are many times higher than those of stabilized zirconia-based solid electrolyte at corresponding temperatures. The ratio of Emeas./Ecalc. of an oxygen concentration cell Pt∣O2(air)∣Bi2O3?Y2O3∣O2(pure oxygen)∣Pt is close to 1 which shows that the materials containing 22.5 to 30 mol% Y2O3 are nearly pure ionic conductors. The p-type conductivity is negligible at higher PO2 values. The n-type conduction for a sample containing 27.5 mol% Y2O3 was investigated using the Coulomb titration technique in which the following cell was used: Pt Rh∣O2(air)∣Bi2O3?Y2O3∣[O]sn∣W.log Pé=-767000/T+665. Pé is equal to 2.6×10-61 atm at 800°C. The n-type conductivity is also very small. Thus these materials are good oxygen ionic conductors. 相似文献