Luminescent properties of Bi-doped boro-alumino-phosphate glasses

A new Bi-doped boro-alumino-phosphate glass (BAP) composition was developed. Absorption and emission spectra and luminescence decay kinetics were investigated. The emission spectrum consists of two wide bands in the visible (0.6–0.8 μm) and near-infrared (∼1.0–1.5 μm) ranges. The luminescence decay curve investigation has revealed a complicated behavior dependent on both excitation and registration wavelengths. In contrast to earlier investigated Bi-doped glasses, Bi:BAP has good technological properties and can be easily scaled. This makes the developed glass composition interesting for broadband tunable (∼1.0–1.5 μm) lasers and amplifiers. PACS 32.70.Cs; 78.20.-e; 78.55.Qr     

Luminescent properties of AIIB2IIIC4VI compounds

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 3, pp. 145–151, May–June, 1995.     

Synthesis and thermoelectric properties of Bi-doped SnSe thin films

Bi doped n-type SnSe thin films were prepared by chemical vapor deposition (CVD) and their structure and thermoelectric properties were studied. The x-ray diffraction patterns, x-ray photoelectron spectroscopy, and microscopic images show that the prepared SnSe thin films were composed of pure SnSe crystals. The Seebeck coefficients of the Bi-doped SnSe were greatly improved compared to that of undoped SnSe thin films. Specifically, Sn_0.99Bi_0.01Se thin film exhibited a Seebeck coefficient of -905.8μV·K^-1 at 600 K, much higher than 285.5 μV·K^-1 of undoped SnSe thin film. Further first-principles calculations reveal that the enhancement of the thermoelectric properties can be explained mainly by the Fermi level lifting and the carrier pockets increasing near the Fermi level due to Bi doping in the SnSe samples. Our results suggest the potentials of the Bi-doped SnSe thin films in thermoelectric applications.     

Luminescent properties of Dy doped SrMoO4 phosphor

Trivalent dysprosium ions (Dy³⁺) doped strontium molybdate (SrMoO₄) phosphors were synthesized by solid-state reaction and their photoluminescence (PL) properties were investigated. X-ray powder diffraction (XRD) analysis confirmed the formation of SrMoO₄:Dy³⁺. PL measurements indicated that the phosphor exhibited intense emission at 482, 490 (⁴F_9/2→⁶H_15/2) and 575 nm (⁴F_9/2→⁶H_13/2) under UV excitation. The effect of the doping concentration of Dy³⁺in SrMoO₄:Dy³⁺ on the PL was investigated in detail. Na⁺ ion was a good charge compensator for SrMoO₄:Dy³⁺.     

掺铋离子BaO-B203玻璃的制备及其近红外发光性能的研究

采用高温熔融法制备了掺Bi离子的BaO—B203玻璃,测定了样品玻璃的近红外以及可见光区的激发、发射谱、荧光衰减曲线以及Raman光谱．在808nm波长光的激发下,在掺Bi离子的BaO—B203玻璃中发现了近红外发光现象．且存在多个发光峰．讨论了玻璃网络结构对Bi离子发光的影响,对其发光机理进行了初步的探讨．     

掺铋BaF2晶体的制备及其近红外发光研究

通过温度梯度法制备了Bi₂O₃:BaF₂以及BiF₃:BaF₂晶体.在Bi₂O₃:BaF₂晶体中观察到了发光峰位于961 nm,半高宽202 nm的超宽带红外发光.在BiF₃:BaF₂晶体中检测到Bi²⁺和Bi³⁺可见区的发光,但是没有观察到红外发光.通过γ射线辐照实现了BiF₃:BaF₂晶体的近红外发光, 发光峰位于1135 nm,半高宽192 nm.讨论了Bi₂O₃和BiF₃掺杂BaF₂晶体的红外发光的机理. 关键词： 近红外发光 铋 氟化钡晶体 γ辐照     

Luminescent properties of erbium-activated glasses

The spectra, intensity, and duration of trivalent erbium luminescence in a large number of inorganic glasses of various compositions were investigated. The observed absorption and luminescence bands were attributed to transitions between certain^sL_j levels of the Er³⁺ ion. It is shown that in all cases the principal portion of the luminescence yield was associated with the⁴I_13/2 ⁴I_15/2 transition band with _max = 6500 cm^–1. The effects of glass composition, activator concentration, and temperature on the yield and duration of luminescence in the 6500 cm^–1 band were studied. An investigation of the effect of temperature on the structure of this band was used to construct a diagram of the crystalline splitting of the⁴I_13/2 and⁴I_15/2 levels in glass.     

掺Bi钨酸镉单晶体发光特性的研究

用坩埚下降法(Bridgman)生长出了Bi离子掺杂的CdWO₄单晶.测定了晶体不同部位的吸收光谱、发射光谱和X射线电子能谱(XPS).Bi离子的掺入引起CdWO₄晶体的吸收边从345 nm红移到399 nm.在311 nm, 373 nm,808 nm和980 nm光的激发下,分别观测到中心波长为470 nm,528 nm,1078 nm和较弱的1504 nm四个不同发射带.Bi:CdWO₄单晶的XPS谱分别与Bi₂ 关键词： Bi离子 荧光光谱 X射线电子能谱 4单晶')" href="#">CdWO₄单晶     

铋离子掺杂RO-Al2O3-SiO2玻璃近红外超宽带发光性质

研究了碱土金属氧化物对Bi离子掺杂RO-Al₂O₃-SiO₂ (R=Ca, Sr, Ba)玻璃近红外超宽带发光性质的影响. 结果表明: 玻璃样品在不同抽运源激发下都可检测到较强的近红外超宽带发光. 在808 nm激光激发下, 随着碱土金属离子半径的增加, Bi离子在1 300 nm附近的近红外发光强度显著增加, 荧光半高宽逐渐增加, 其荧光寿命最长可超过600 μms; 而在690 nm激光激发下, 随着碱土金属离子半径的增加, Bi离子在1 100 nm附近的近红外发光呈减弱趋势, 荧光半高宽逐渐增大, 半高宽最大可超过400 nm. 近红外发光可能源于两种不同形式铋的发光中心. 针对上述结果探讨了该玻璃体系中Bi离子近红外发光的机理.     

Dielectric properties of polycrystalline ferrites

The well-known dielectric relaxation of polycrystalline ferrites is usually seen as being related to an inhomogeneous polarization. According to that theory, the inhomogeneities are formed by poorly conducting grain boundaries in the well-conducting bulk material. Experimental results reported here suggest, that in some cases the dispersions are not due to an inhomogeneity polarization. Previously reported results of measurements taken on single crystals are also inconsistent with this model. Therefore an electric dipole relaxation model is introduced.     

Magnetic properties of Bi-doped Y3Fe5O12 nanoparticles

Bi³⁺ substituted garnet nanoparticles Y_3−xBi_xFe₅O₁₂ (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2 and 1.3) were fabricated by a sol–gel method and their crystalline structures and magnetic properties were investigated by using X-ray diffraction (XRD), IR spectroscopy, thermal gravity analysis–differential thermal analysis (TG-DTA), transmission electron microscope (TEM), Mössbauer spectroscopy and vibrating sample magnetometer (VSM). The XRD patterns of Y_3−xBi_xFe₅O₁₂ have only peaks of the garnet structure. From the results of VSM, it is shown that the saturation magnetization of sample is decreased with increasing the content of Bi ions. Meanwhile, it is observed that with the enhancement of the single magnetic domains surface spin effects, the saturation magnetization is raised as the particle size of samples is increased.     

Luminescent properties of doped dielectric nanocrystals

Taking into account electron-phonon interaction effects, we have studied the radiative characteristics of doped nanoellipsoids in a dielectric medium with an arbitrary fraction of nanoparticles in a nanocomposite. The obtained analytical expressions for the radiative characteristics allow it to be concluded to what extent they are susceptible to changes in the phonon subsystem and electron-phonon interaction caused by the spatial confinement effect.     

Luminescent properties of LiCl-Cu single crystals

The absorption, photoluminescence, x-ray luminescence, and thermoluminescence spectra, and the photoluminescence excitation spectra of LiCl-Cu single crystals with different activator concentration were investigated at temperatures of 79–450°K. The absorption spectrum at room temperature has two bands with maxima at 237 and 259 nm. The absorption coefficient of the 237 nm band is proportional to the copper concentration in the crystal (C_Cu ≤ 7·10^?4 mole %). The photoluminescence and x-ray luminescence spectrum at room temperature consists of one emission band at 324 nm, which conforms with the Mollwo-Ivey rule in the homologous series RbCl → KCl → NaCl → LiCl. The copper ions create trapping levels for electrons and holes at different depths in the forbidden band of the LiCl crystal. The correlation between the thermoluminescence peaks and the recombination-luminescence excitation bands (infrared stimulation) is investigated.     

Luminescent properties of Yb-doped LaSc3(BO3)4 under VUV excitation

Ytterbium doped borate crystals are promising laser media, e.g. in ${\mathrm{LaSc}}_3({\mathrm{BO}}_3{)}_4$ (LSB) matrices large distance between ytterbium ions results in reduced concentration quenching of the ytterbium f–f luminescence [Petermann, K., Fagundes-Peters, D., Johansen, O., Mond, M., Peters, V., Romero, J.J., Kutovoi, S., Speiser, J., Giesen, A., 2005. Highly Yb-doped oxides for thin-disc lasers. J. Crystal Growth 275, 135-140]. ${\mathrm{Yb}}^{3+}$ ions in complex oxides in addition to the 4f $\to$ 4f transitions often manifest fast charge transfer luminescence (CTL) in the UV-visible range. In some borates it was not observed at all, like in orthoborates of Sc, Y and La [Van Pieterson, L., Heeroma, M., de Heer, E., Meijerink, A., 2000. Charge transfer luminescence of ${\mathrm{Yb}}^{3+}$. J. Lumin. 91, 177–193]; in haloborates ${\mathrm{Sr}}_2{\mathrm{B}}_5{\mathrm{O}}_9\mathrm{X}$, where X = Cl, Br, the UV/visible luminescence was attributed to ytterbium CTL though it looked substantially different from other matrices [Dotsenko, V.P., Berezovskaya, I.V., Pyrogenko, P.V., Efryushina, N.P., Rodniy, P.A., Eijk van, C.W.E., Sidorenko, A.V., 2002. Valence states and luminescence properties of ytterbium ions in strontium haloborates. J. Solid State Chem. 166, 271–276]; while in oxyborate ${\mathrm{Li}}_2{\mathrm{Lu}}_5{\mathrm{O}}_4({\mathrm{BO}}_3{)}_3$ “classical” CTL was observed [Jubera, V., Garcia, A., Chaminade, J.P., Guillen, F., Sablayrolles, Jean, Fouassier, C., 2007. ${\mathrm{Yb}}^{3+}$ and ${\mathrm{Yb}}^{3+}\text{-}{\mathrm{Eu}}^{3+}$ luminescent properties of the ${\mathrm{Li}}_2{\mathrm{Lu}}_5{\mathrm{O}}_4({\mathrm{BO}}_3{)}_3$ phase. J. Lumin. 124(1), 10–14]. In this work the luminescence properties of another borate, namely LSB doped by Yb are presented.     

CaWO4：Sm3+荧光粉的发光性质及其能量传递机理

采用沉淀法制备了不同Sm³⁺掺杂浓度的白钨矿结构CaWO₄荧光粉材料. 对CaWO₄:Sm³⁺ 材料的光致发光性质的研究结果表明, 在404 nm光照下样品可以实现色纯度较高的红光发射, 而短波紫外240 nm光照下除Sm³⁺的特征发射外还能观察到CaWO₄自激发发射, 能够获得较强的白光; 实验发现Sm³⁺掺杂浓度为2%时样品的发光强度最高; 通过对实验数据的分析确定了Sm³⁺之间的能量传递类型为电偶极-电偶极相互作用, 并计算了能量传递的临界距离大约为2.0 nm. 关键词： 光致发光 4：Sm³⁺')" href="#">CaWO₄：Sm³⁺ 荧光寿命 能量传递