共查询到20条相似文献,搜索用时 15 毫秒
1.
M. Elisa Cristiana Grigorescu Ileana Vasiliu M. Bulinski V. Kuncser Dana Predoi G. Filoti Aurelia Meghea Nicoleta Iftimie Maria Giurginca C. Onose 《Optical and Quantum Electronics》2007,39(4-6):523-531
The paper deals with optical and electronic properties of the aluminophosphate glasses containing Fe–Mn and Fe–Cr ion pairs in different concentration. The influence of the mixed alkali ions over the electronic properties has been investigated. The optical behavior (optical transmission) of the glass samples has been studied by UV-VIS spectroscopy and the refractive index dependency on wavelength has been discussed. The transmission spectra show features specific for the doping transition ions (TM), revealing different oxidation states of iron (Fe2+/Fe3+), manganese (Mn2+/Mn3+) and chromium (Cr3+/Cr6+) in the vitreous network. Mössbauer spectroscopy offers information regarding the TM oxidation states, redox processes and the iron coordination symmetry in the vitreous network. In the case of Fe–Mn doped glasses, the percentage of Fe2+ is about 40% and a doubled iron content leads to an increasing of Fe2+ percentage up to 53%. The replacing of lithium ions by natrium ions (mixed alkali effect) provides an increasing of the Fe2+ percentage up to 56%. The occurrence of the tetrahedral or octahedral symmetry of Fe2+ ions bonded by O2? ions depends on the transition ion nature and Li+/Na+ ratio. Infrared absorption spectra of the pair transition ions-doped aluminophosphate glasses reveal optical phonons specific for the phosphate glass matrix. 相似文献
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This study deals with the results on the concentration-dependent fluorescence properties of Tb3+-doped calcium aluminosilicate (CAS) glasses of composition (100−x)(58SiO2–23CaO–5Al2O3–4MgO–10NaF in mol%)-x Tb2O3 (x=0, 0.25, 0.5, 1, 2, 4, 8, 16, 24, 32, 40 in wt%). The FTIR reflectance spectra suggested the role of dopant ions as network modifiers in the glass network. The fluorescence spectra of low Tb3+-doped glasses have revealed prominent blue and green emissions from 5D3 and 5D4 excited levels to 7Fj ground state multiplet, respectively. The glass with 2 wt% of Tb2O3 has exhibited maximum intensity of blue emission from 5D3 level, while green emission from 5D4 level has increased linearly up to 24 wt% and showed reduction in the rate of increase for higher Tb2O3 concentrations. The concentration quenching of blue emission (5D3→7Fj) is attributed mainly to the resonant energy transfer (RET) assisted cross-relaxation (CR) among the excited and nearest neighbour unexcited Tb3+ ions in the glass matrix. The decline in rate of increase of green emission (5D4→7Fj) at higher concentrations has been explained due to a possible occurrence of cooperative energy transfers leading to 4f8→4f75d transition interactions. The blue and green emission decay kinetics have been recorded to compute the excited level (5D3 and 5D4) lifetimes, which confirmed the Tb3+ concentration quenching of the blue emission in these glasses. 相似文献
4.
The optical spectra and electron paramagnetic resonance (EPR) g and A factors of calcium aluminoborate glasses (CaAB) : VO2+ are calculated using a complete diagonalization (of the energy matrix) process (CDP). Good agreement between the theoretical values and experimental results indicates the effectiveness of the CDP method for theoretical studies of optical and EPR spectra of 3d1 (or V4+) ions in glasses. 相似文献
5.
The spectroscopic and laser properties of Nd3+ and Dy3+ ions in lead borate glass were studied. Luminescence spectra recorded in the near-infrared and visible ranges correspond to 4F3/2-4IJ/2 (J=9, 11, 13) transitions of Nd3+ and 4F9/2-6HJ/2 (J=11, 13, 15) transitions of Dy3+, respectively. Luminescence decay curves were analyzed as a function of activator concentration. Luminescence quenching is observed, which is due to Ln-Ln interaction increasing. Several spectroscopic parameters relevant to laser potential of Ln3+ ions (Ln=Nd, Dy) in lead borate glass were determined. The relatively large values of the quantum efficiency and the room-temperature emission cross-section for the 4F3/2-4I11/2 transition of Nd3+ at 1061 nm and the 4F9/2-6H13/2 transition of Dy3+ at 573 nm imply that Ln-doped lead borate glasses can be considered as promising solid-state materials for laser applications. 相似文献
6.
The glass forming regions have been determined in the systems P2O5-A2O-MO (A = Li, Na; M = Cu, Cd), P2O5-Bi2O3-Li2O and P2O5-Bi2O3-ZnO. The largest vitreous domain has been found in the ternary diagram P2O5-Bi2O3-ZnO. The variation of the dielectric constants has been followed inside the glass regions. ε'r increases with increasing amount of alkaline oxides and substantially diminishes with increasing percentage of either CuO or CdO. 相似文献
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Xiaoluan Liang Chaofeng Zhu Yunxia Yang Shuanglong Yuan Guorong Chen 《Journal of luminescence》2008,128(7):1162-1164
Phosphate glasses doped with Dy3+ ions and co-doped with Dy3+–Tm3+ ions are successfully prepared in the present work. Their photoluminescence properties have been studied by absorption, excitation and emission spectra. A combination of blue and yellow emissions has emerged in the glasses, which allows the observation of white light when the glasses are excited by the ultraviolet light. The emission intensity of Dy3+ is influenced by the system ionicity, while the intensity ratio of yellow to blue emissions from Dy3+ can be tuned by varying both the concentration of Tm3+ ion and the glass matrix composition. 相似文献
9.
Rare earth-doped sodium–gadolinium phosphate glasses with increased luminescence efficiency are promising materials for the detection of neutrons, γ- and X-rays. Their main advantages are low cost, high radioluminescence light output, high quality and chemical durability. The glasses were prepared by a rapid quenching technique in air. The radioluminescence intensity maximum was achieved for a Ce concentration of 3 mol% and that of Gd around 30%. Glass transition temperatures were above 300°C for the tested samples and this guarantees that the glass can be utilised in a sufficiently broad temperature range. The glass-forming ability of this glass system is high. However, until now high-quality glass has been only prepared with a Gd concentration of 40 mol% in the starting batch. The glasses containing at least 30 mol% Gd were moisture resistant, while those with lower Gd concentrations were slightly hygroscopic. 相似文献
10.
测试了不同掺杂浓度和不同厚度下Yb3+ 磷酸盐玻璃的吸收光谱、荧光光谱和荧光寿命 ,计算了积分吸收截面、吸收截面、受激发射截面、自发辐射寿命以及荧光有效线宽等光谱参数 ,讨论了荧光俘获效应对Yb3+ 磷酸盐玻璃光谱性质的影响 .结果表明荧光俘获效应随样品厚度和掺杂浓度的增加而增大 .由于荧光俘获效应的存在使得测量的Yb3+ 磷酸盐玻璃荧光寿命明显长于计算的荧光寿命 ,在 0 2mol%Yb2 O3低掺杂浓度下采用不同厚度 ( <4mm)的样品测量的荧光寿命之间误差为 3 0 %左右 ,高浓度 ( 6mol%Yb2 O3)掺杂下误差可达 43 % .荧光俘获还造成荧光谱线加宽 ,导致荧光有效线宽在低浓度 ( 0 2mol%Yb2 O3)时增加 14% ,在高掺杂浓度 ( 6mol%Yb2 O3)下增加 3 0 %以上 相似文献
11.
Structural analysis of x[(100−y)Ag2O·yMnO]·(100−x)[2B2O3·As2O3] glasses, with x=10 mol% and 0≤y≤10 mol%, was performed by means of FT-IR and FT-Raman spectroscopies. The purpose of this work is to investigate the structural changes that appear in the xAg2O·(100−x)·[2B2O3·As2O3] glasses with the addition and increase in manganese ions content. FT-IR measurements revealed the presence of pyro-, ortho-, di-, tri-, tetra- and penta-borate groups and structural units characteristic to As2O3 in the structure of the studied glasses. FT-IR spectroscopy measurements also show that BO3 units are the main structural units of the glass system. The presence of structural units characteristic to Ag2O were not directly evidenced by FT-IR spectroscopy. In addtition, the FT-Raman analysis evidenced the presence of boroxol rings in the structure of the studied glasses. 相似文献
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New fluorophosphate glasses based on MnF2, NaPO3 and MFn (M=Zn2+, Sr2+, Mg2+, Ba2+, Li+, Na+ and K+) have been synthesised and characterized. Large vitreous areas were observed. Samples of 4 mm in thickness have been obtained. These glasses are easy to prepare and stable in ambient air. Depending on the composition and the nature of the M cation, glass transition temperature, Tg, lies between 230 and 314 °C, crystallisation temperature, Tx is between 320 and 475 °C. These glasses are pink coloured, and infrared transmission extends up to 4.5 μm with extrinsic OH− absorption band at 3200 cm−1 and other bands around 2200 and 1600 cm−1 that relate to PO4 tetrahedron vibration. Other physical properties including density, microhardness, Young modulus, thermal expansion and refractive index were investigated and correlated to composition. 相似文献
14.
The glass samples [40SiO2?+?5Al2O3?+?{55???x}Na2O?+?xMnO2] where x?=?0.05, 0.2, 0.4, 0.6, 0.8, and 1?mol% MnO2 before and after being heat treated were subjected to X-ray diffraction. The diffraction lines provided clear evidence of the nucleation and growth, which are characteristic of sodium silicate phase. Crystallization studies were conducted using differential thermal analysis. Crystallization peak temperatures were identified and the transformed fractions were determined. Both the rate of growth, K 0, and the activation energy, E, depend on the influence of manganese ions in the glass network as a modifier or as a former and the manganese content. The values of the Avrami parameter, n, were calculated using two methods and were in excellent agreement. The process of nucleation and growth rate depends on the manganese content. 相似文献
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Nonlinear optical characterization of phosphate glasses based on ZnO using the Z-scan technique
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Masoumeh Shokati Mojdehi Wan Mahmood Mat Yunus Khor Shing Fhan Zainal Abidin Talib N. Tamchek 《中国物理 B》2013,22(11):117802-117802
The nonlinear optical properties of a phosphate vitreous system [(ZnO)x-(MgO)30-x-(P2 O5)70], where x=8, 10, 15, 18, and 20 mol% synthesized through the melt-quenching technique have been investigated by using the Z-scan technique. In the experiment, a continuous-wave laser with a wavelength of 405 nm was utilized to determine the sign and value of the nonlinear refractive (NLR) index and the absorption coefficient with closed and opened apertures of the Z-scan setup. The NLR index was found to increase with the ZnO concentration in the glass samples by an order of 10-10 cm2·W-1. The real and imaginary parts of the third-order nonlinear susceptibility were calculated by referring to the NLR index (n2) and absorption coefficient (β) of the samples. The value of the third-order nonlinear susceptibility was presented by nonlinear refractive or absorptive behavior of phosphate glasses for proper utilization in nonlinear optical devices. Based on the measurement, the positive sign of the NLR index shows a self-focusing phenomenon. The figures of merit for each sample were calculated to judge the potential of phosphate glasses for application in optical switching. 相似文献
16.
测试了不同掺杂浓度和不同厚度下Yb3+磷酸盐玻璃的吸收光谱、荧光光谱和荧 光寿命,计算了积分吸收截面、吸收截面、受激发射截面、自发辐射寿命以及荧光有效线宽等光谱参数,讨论了荧光俘获效应对Yb3+磷酸盐玻璃光谱性质的影响.结果表明荧光俘 获效应随样品厚度和掺杂浓度的增加而增大.由于荧光俘获效应的存在使得测量的Yb3+磷酸盐玻璃荧光寿命明显长于计算的荧光寿命,在0.2mol%Yb2O3低掺 杂浓度下
关键词:
荧光俘获
掺镱磷酸盐玻璃
荧光光谱 相似文献
17.
Silver-doped calcium phosphate nanopowders were successfully prepared by the cost-effective electrostatic spray-pyrolysis
process. The properties of the silver-doped nanopowder annealed at 500°C for 30 min were investigated through X-ray diffraction
analysis, field emission scanning electron microscope, and Fourier transform infrared spectroscopy. The silver-doped nanopowders
with 70–90 nm particle size showed an antibacterial performance against Escherichia coli. 相似文献
18.
R.S. Muralidhara J.L. Rao R.V. Anavekar 《Journal of Physics and Chemistry of Solids》2010,71(12):1651-1655
Electron paramagnetic resonance (EPR) and optical absorption spectral investigations have been carried out on Fe3+ ions doped sodium borophosphate glasses (NaH2PO4-B2O3-Fe2O3). The EPR spectra exhibit resonance signals with effective g values at g=2.02, g=4.2 and g=6.4. The resonance signal at g=4.2 is due to isolated Fe3+ ions in site with rhombic symmetry whereas the g=2.02 resonance is due to Fe3+ ions coupled by exchange interaction in a distorted octahedral environment. The EPR spectra at different temperatures (123-295 K) have also been studied. The intensity of the resonance signals decreases with increase in temperature whereas linewidth is found to be independent of temperature. The paramagnetic susceptibility (χ) was calculated from the EPR data at various temperatures and the Curie constant (C) and paramagnetic Curie temperature (θp) have been evaluated from the 1/χ versus T graph. The optical absorption spectrum exhibits bands characteristic of Fe3+ ions in octahedral symmetry. The crystal field parameter (Dq) and the Racah interelectronic repulsion parameters (B and C) have also been evaluated and discussed. 相似文献
19.
Preparation and optical spectroscopy of phosphate glasses containing divalent europium ions 总被引:1,自引:0,他引:1
P2O5.BaO.Na2O.K2O glasses doped with various content of Eu2O3 were prepared using high temperature melting method, and the Eu2+ ions in the phosphate glasses were obtained with the aid of the reductive action of silicon powder. The fabricating conditions, fluorescence, excitation spectra of the glasses were then studied. The glasses containing europium show a broad emission band at 450 nm and sharp bands from 580 to 650 nm, and the co-existence of Eu2+ and Eu3+ is identified. Also, a good glass with a dominant proportion and large quantity of Eu2+ ions can be obtained by the reductive action of silicon powder and proper processing. 相似文献
20.
T. Satyanarayana 《Journal of luminescence》2010,130(3):498-506
The glasses of the composition (39−x)BaO-xAl2O3-60P2O5:1.0Ho2O3 (in mol%) with x value ranging from 1.0 to 4.0 have been synthesized. The IR spectral studies of these glasses have indicated that there is a gradual transformation of Al3+ ions from tetrahedral to octahedral with increase in the concentration of Al2O3 up to 3.0 mol%. Optical absorption and fluorescence spectra (in the visible and NIR regions) of these glasses have been recorded at room temperature. The Judd-Ofelt theory could successfully be applied to characterize the absorption and luminescence spectra of Ho3+ ions in these glasses. From the luminescence spectra, various radiative properties like transition probability A, branching ratio βr, the radiative lifetime τr and emission cross-section σE for various emission levels of these glasses have been evaluated. The radiative lifetime of the 5S2→5I8 (green emission) transition has also been measured. The variations observed in these parameters have been discussed in the light of varying co-ordinations (tetrahedral and octahedral positions) of Al3+ ions in the glass network. The influence of hydroxyl groups on the luminescence efficiency of the transition 5S2→5I8 has also been discussed. Finally the optimum concentration of Al2O3 for getting maximum luminescence output has also been identified and reported. 相似文献