共查询到20条相似文献,搜索用时 0 毫秒
1.
Kaushik Biswas Sathravada Balaji Debarati Ghosh Annapurna Kalyandurg 《International Journal of Applied Glass Science》2017,8(2):204-215
In this work, effect of glass composition as well as ceramization on visible and near-infrared (NIR) luminescence properties along with their decay dynamics of Er3+ ions has been compared considering two different oxyfluoride glasses yielding BaF2 and BaGdF5 nanocrystals. Both the glass systems have exhibited an intense normal and upconversion green emission under ultraviolet (378 nm) and NIR (978 nm) excitations, respectively. A remarkable enhancement of these emission intensities is observed for gadolinium-(Gd) containing glasses. Interestingly, NIR fluorescence intensity from Er3+ ions at 1540 nm has showed marginal decrease in gadolinium-containing glass which is attributed to occurrence of strong excited-state absorption (ESA) due to higher fluorine content ensuing an augmentation of upconversion green emission with a concomitant decrease in NIR emission. The quadratic dependence of upconversion green emission intensity on its pump power for all the samples revealed biphotonic absorption process from ground-state 4I15/2 to the excited-state 4I11/2 followed by ESA of second photon to the 4F7/2 level. The intense green upconversion emission as well as enhanced NIR fluorescence lifetimes indicate the suitability of these glass/glass ceramics for upconversion lasers and amplification in the third telecom window. 相似文献
2.
Wavelength converters in white light-emitting diodes are usually made by sintering of phosphor-glass powder compacts. An issue is that the sintering process usually results in the reduction of phosphor amount. In the present study, composites containing CaAlSiN3:Eu2+ red phosphor and Bi2O3-B2O3-ZnO-Sb2O5 glass were fabricated by sintering method. Influences of CaAlSiN3:Eu2+ phosphor content (10 vol%–30 vol%) and sintering temperature (410–430°C) on the residual amount of the phosphor phase and the resulting luminescence intensity of the composites were investigated. The change of CaAlSiN3:Eu2+ content due to sintering was analyzed by X-ray diffraction. The interdiffusion between the CaAlSiN3:Eu2+ and glass matrix was examine by scanning electron microscope equipped with energy dispersive X-ray spectrometry. This paper focuses on the change of luminescence intensity after sintering. It was found that although the content of phosphor CaAlSiN3:Eu2+ reduces after sintering; the luminescent intensity of the composites anomalously increases. The optimum luminescence intensity is 14% higher than that of the as-mixed, unfired powder. It is proposed that the incorporation of Bi3+ ions from the glass matrix into the phosphor CaAlSiN3:Eu2+ during sintering improves the luminescence ability of the phosphor particles. 相似文献
3.
Investigation of optical properties: Eu with Al codoping in aluminum silicate glasses and glass‐ceramics 下载免费PDF全文
Eu‐doped transparent oxyfluoride aluminosilicate glass was prepared by controlling with Al codoping of melt‐quenched glass fabricated under air atmosphere. In the presence of Al input, the photoluminescence emission spectra under 393 nm excitation shows a blue shift by adjusting the ratio of Eu3+ and Eu2+. After heat treatment of glass, the ratio of Eu3+ and Eu2+ of luminescence emission were changed by controlling treatment temperature. The PL intensity of Eu3+ and Eu2+ ions in the glass‐ceramics (GC) was much stronger than in the precursor glass (PG). The possible mechanism responsible for color tuneability of the ratio of Eu3+ and Eu2+ doped was discussed. 相似文献
4.
Structural and luminescence properties of silica powders and transparent glass‐ceramics containing LaF3:Eu3+ nanocrystals 下载免费PDF全文
Natalia Pawlik Barbara Szpikowska‐Sroka Ewa Pietrasik Tomasz Goryczka Wojciech A. Pisarski 《Journal of the American Ceramic Society》2018,101(10):4654-4668
In this work, silica powders and transparent glass‐ceramic materials containing LaF3:Eu3+ nanocrystals were synthesized using the low‐temperature sol‐gel technique. Prepared samples were characterized by TG/DSC analysis as well as X‐ray diffraction and IR spectroscopy. The transformation from liquid sols toward bulk powders and xerogels was also examined and analyzed. The optical behavior of prepared Eu3+‐doped sol‐gel samples were evaluated based on photoluminescence excitation (PLE: λem = 611 nm) and emission (PL: λexc = 393 nm, λexc = 397 nm) spectra as well as luminescence decay analysis. The series of luminescence lines located within reddish‐orange spectral scope were registered and identified as the intra‐configurational 4f6‐4f6 transitions originated from Eu3+ optically active ions (5D0 → 7FJ, J = 0‐4). Moreover, the R/O‐ratio was also calculated to estimate the symmetry in local framework around Eu3+ ions. The luminescence spectra and double‐exponential character of decay curves recorded for fabricated nanocrystalline sol‐gel samples (τ1(5D0) = 2.07 ms, τ2(5D0) = 8.07 ms and τ1(5D0) = 0.79 ms, τ2(5D0) = 9.76 ms for powders and glass‐ceramics, respectively) indicated the successful migration of optically active Eu3+ ions from amorphous silica framework to low phonon energy LaF3 nanocrystal phase. 相似文献
5.
Jingtao Zhao Lihui Huang Shilong Zhao Shiqing Xu 《Journal of the American Ceramic Society》2019,102(4):1720-1725
Tb3+-doped germanate glass ceramics containing CaF2 nanocrystals were prepared by melt quenching method with subsequent heat treatment. Their microstructures were investigated by XRD and TEM techniques. Their optical properties were studied by the transmittance, the photoluminescence, and the X-ray excited luminescence (XEL). The luminescence intensity in the glass ceramics under 377 nm light and X-ray excitations is significantly enhanced. The maximum integrated XEL intensity of the glass ceramics is about 50% of that of the commercial Bi4Ge3O12 (BGO) scintillating crystal. The results indicate that Tb3+-doped germanate glass ceramic could be a promising scintillating material used in X-ray detection for slow event. 相似文献
6.
Haotian Wang Guodong Zhang Tianli Zhao Chunhui Su Xiangyu Zou Hongbo Zhang 《International Journal of Applied Ceramic Technology》2023,20(6):3743-3753
The Tb3+-doped transparent glass ceramics containing Al4Ti2SiO12 crystal are synthesized by the melt-solid-crystallization method. The optimal heat treatment conditions for the glass ceramic samples are determined to be 750°C, 1.5 h based on differential scanning calorimeter, X-ray diffractometer, scanning electron microscope, and light transmittance curve. The luminescence properties of the glass ceramics samples are characterized by a fluorescence spectrometer. The emission spectrum revealed that the dominant emission is green attributed to Tb3+, the optimal doping concentration is 0.3%. And the thermal quenching activation energy of 0.3% Tb3+-doped glass ceramics is 0.2554 eV, while the relative sensitivity is 1.50% K−1 at 298 K and the absolute sensitivity is 2.27×10−2 K−1 at 418 K through variable temperature fluorescence spectroscopy test and a series of calculations. These findings demonstrate the excellent stability and temperature sensitivity of glass ceramics, thereby highlighting their potential for use in green lighting and temperature sensing applications. 相似文献
7.
8.
Hiroaki Furuse Shunsuke Nakasawa Hidehiro Yoshida Koji Morita Tohru S. Suzuki Byung‐Nam Kim Yoshio Sakka Keijiro Hiraga 《Journal of the American Ceramic Society》2018,101(2):694-702
Conventional ceramic processing techniques do not produce ultrafine‐grained materials. However, since the mechanical and optical properties are highly dependent on the grain size, advanced processing techniques are needed to obtain ceramics with a grain size smaller than the wavelength of visible light for new laser sources. As an empirical study for lasing from an ultrafine‐grained ceramics, transparent Yb3+:Y2O3 ceramics with several doping concentrations were fabricated by spark plasma sintering (SPS) and their microstructures were analyzed, along with optical and spectroscopic properties. Laser oscillation was verified for 10 at.% Yb3+:Y2O3 ceramics. The laser ceramics in our study were sintered without sintering additives, and the SPS produced an ultrafine microstructure with an average grain size of 261 nm, which is about one order of magnitude smaller than that of ceramics sintered by conventional techniques. A load was applied during heating to enhance densification, and an in‐line transmittance near the theoretical value was obtained. An analysis of the crystal structure confirmed that the Yb3+:Y2O3 ceramics were in a solid solution. To the best of our knowledge, this study is the first report verifying the lasing properties of not only ultrafine‐grained but also Yb‐doped ceramics obtained by SPS. 相似文献
9.
红色荧光粉YAl3(BO3)4:Eu3+的制备及发光性能研究 总被引:1,自引:0,他引:1
以稀土氧化物、硝酸铝和硼酸为原料,高温固相反应制备了单相红色荧光粉YAl3(BO3)4:Eu3+,用X射线衍射和发射光谱对荧光粉末的结构和发光性能进行了分析.研究了煅烧温度、Eu3+掺杂量对其发光性能的影响.结果表明,反应物在1 250 ℃下煅烧可制得单相YAl3(BO3)4:Eu3+晶体,在YAl3(BO3)4:Eu3+晶体中,Eu3+取代了YAl3(BO3)4晶体中Y3+,占据了非对称中心格位.在394 nm的紫外光激发下,YAl3(BO3)4:Eu3+荧光粉具有很强的发光性能,与(Y,Gd)BO3:Eu3+荧光粉相比,最强发射线波长由596 nm变为618 nm,由橙红色光变为红色光,色纯度有了很大提高.Eu3+的最佳掺杂量为8%(物质的量分数). 相似文献
10.
Bright red luminescent Eu3+ doped polyvinyl alcohol (PVA) films were made by solution casting technique. The emission performance of these films was studied from the measurement of excitation, emission, and lifetimes. On irradiation with an UV source, the doped films emitted bright red light. Such luminescent polymer films are expected to find potential applications as new optical materials. Emission process in the system was explained by an energy level scheme. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3273–3276, 2006 相似文献
11.
Xiaosong Lu Zhiqiang Lai Jing Ren Lukas Strizik Tomas Wagner Yanqiu Du Gerald Farrell Pengfei Wang 《Journal of the European Ceramic Society》2019,39(7):2580-2584
The distribution of Tm3+ and Ni2+ ions is unambiguously exhibited in 80GeS2-20Ga2S3 chalcogenide glass ceramics (GCs) containing Ga2S3 nanocrystals (NCs) by using advanced analytical transmission electron microscopy. Distinctively different distribution patterns of Tm3+ and Ni2+ ions are observed in the GCs obtained by controlled crystallization. The distribution of the dopants imposes strong influence on their optical properties which are revealed by absorption and photoluminescence (PL) spectra. Detailed discussions are given of the mechanisms of the crystallization-induced PL enhancement and quenching of the Tm3+ mid-infrared and Ni2+ near-infrared emissions, respectively. 相似文献
12.
研究了SrAl2O4:Eu^2 ,Dy^3 长余辉材料的一种新合成方法。首先利用水热法制备出该发光材料的前驱体,然后将此前驱体粉体在还原气氛下高温烧结,得亮度高,余辉时间长的洲SrAl2O4:Eu^2 ,Dy^3 超细长余辉材料,并对其发光性能进行了研究。并对水热法和复合沉淀法合成的此种材料进行了比较。 相似文献
13.
Tellurium based glasses have interesting thermoelectric characteristics. However, their high electrical resistivity is still an obstacle to considering them for thermoelectric applications. In this work, the (Te85Se15)60???0.6xAs40???0.4xCux glass system was studied. This revealed that Cu can act as glass former and increase both glass thermal stability and electrical conductivity. The best candidate, (Te85Se15)45As30Cu25, was chosen to prepare composites with Bi0.5Sb1.5Te3 using spark plasma sintering. These glass ceramic samples exhibited a much better thermoelectric performance. Glass ceramics with 50?mol. % of Bi0.5Sb1.5Te3 show a maximum ZT value equal to 0.37 at 413?K. Meanwhile, the advantages of glass including low sintering temperature and high formability are well maintained. 相似文献
14.
《Ceramics International》2017,43(16):13199-13205
Crystalline phase evolution through merely adjusting composition was achieved in silicate glass ceramics containing LunOn-1Fn+2 (n = 5–10) nanocrystals. Orthorhombic or cubic phase nanocrystals were precipitated in the aluminosilicate glass matrix after thermal treatment together with varying the Na2O/NaF ratio. Oxyfluoride nanocrystals with quasi-spherical shape show homogenous and dense distribution in glass matrix by transmission electron microscopy measurement. Intense upconversion and mid-infrared emissions were realized in these glass ceramics compared to the precursor glass, and the emission spectral shapes, relative emission intensity and fluorescence decay curves of Er3+ in cubic LuOF embedded samples exhibit remarkable differences due to the crystal phase dependent effect in glass ceramics. These results indicate that the crystallization and luminescence properties of oxyfluoride glass ceramics could be modified through the alteration of glass composition, which could be used for the development of novel glass ceramics and design of luminescent properties. 相似文献
15.
16.
在乙醇和乙二醇的混合溶剂中,用溶剂热法,150℃,反应12 h,成功合成了NaYF4:Eu3+晶体。室温下,用X射线衍射对材料的组成进行了表征,JCPDS号为16-0334。荧光光谱分析表明,在395 nm(7F0→5L4)紫外光激发下,其发射峰在476 nm、540~578 nm、718 nm分别对应着Eu3+的5DJ(J=0,1,2,3)→7FJ(J=1,2,3,4)能级跃迁。并讨论了离子Y3+:Eu3+不同浓度掺杂比对荧光性质的影响。结果表明,Eu3+的最佳掺杂浓度比为5%,当掺杂浓度为10%时,出现荧光猝灭。 相似文献
17.
采用高温固相法合成了白光发光二极管用LiSrPO4:Eu3+红色荧光粉.测量了LiSrPO4:Eu3+的激发和发射光谱,结果显示材料的发射光谱为一系列尖峰,主峰位于616 nm,具有很强的红光发射;激发光谱中O2-→Eu3+的电荷迁移态CTS (220~310 nm)非常低,Eu3+的f→f (310~500 nm)跃迁吸收很强,主峰位于393 nm,与InGaN(350~410 nm)管芯匹配.比较了LiSrPO4:Eu3+与LiCaPO4:Eu3+、LiBaPO4:Eu3+发射光谱的差异,这三种晶体中Eu3+占据的格位对称性按Ca、Sr、Ba顺序逐渐增加.根据Dexter理论判定Eu3+在LiSrPO4中的浓度猝灭机理为电四极-电四极(q-q)相互作用.加入电荷补偿剂Li+、Na+和Cl 均提高了LiSrPO4:Eu3+材料的发射强度.LiSrPO4: Eu3+是一种适合白光发光二极管激发的红色荧光粉. 相似文献
18.
19.
R. Ramaraghavulu K. Pavani P. C. Nagajyothi Jaesool Shim 《Journal of the American Ceramic Society》2023,106(6):3509-3524
Using the melt-quench technique, potassium zinc borophosphate (KZnBP) glasses incorporated with Dy3+, Eu3+, and Dy3+/Eu3+ ions individually and combinedly were prepared, and their photoluminescence (PL)-related features were investigated. The KZnBP glass containing an optimized content of Dy3+ (0.5 mol%) is co-doped with Eu3+ in various contents, and the energy transfer (ET) process between them was studied at λexci = 349, 364, 387 (Dy3+), and 394 nm (Eu3+). The Dy3+/Eu3+ co-doped system, when excited with Dy3+ excitations has resulted in a significant decrease in the intensity of Dy3+ peaks observed at 480 nm (4F9/2→6H15/2, blue) and 574 nm (4F9/2→6H13/2, yellow), with simultaneous enhancement of the intensity of Eu3+ peaks at 591 nm (5D0→7F1, orange) and 617 nm (5D0→7F2, red). This trend is due to the efficient energy transfer from Dy3+ to Eu3+, indicating that Eu3+ ions were sensitized by Dy3+ ions. Dexter's theory and the Inokuti–Hirayama (I–H) model revealed that the dipole–dipole interaction is accountable for the energy transfer from Dy3+ to Eu3+ through energy-transfer channels [4F9/2(Dy3+)+7F1,2(Eu3+)→6H15/2(Dy3+)+5D2(Eu3+)] and [4F9/2(Dy3+)+7F0(Eu3+)→6H13/2(Dy3+)+5D0(Eu3+)]. The color coordinates of the Dy3+/Eu3+ co-doped glasses under various excitations fall within the white light emission spectrum, indicating their potential application in warm white LEDs. 相似文献
20.
DanYu Zhang YuXuan Luo ShuJun Xu LianJie Li JunYu Chen Lei Lei Hai Guo 《Journal of the American Ceramic Society》2023,106(10):5887-5897
In this paper, Y4GeO8:Bi3+,Eu3+ phosphor with dual emission centers was elaborated via conventional solid-state reaction technology. Thorough research on the structure, morphology, and luminous properties of Y4GeO8:Bi3+,Eu3+ phosphor, the potential applications in optical thermometry were investigated by means of fluorescence intensity ratio and thermochromic techniques. Under 290 and 347 nm excitation, Y4GeO8:Bi3+,Eu3+ phosphor presents broadband emission from 3P1 → 1S0 transition of Bi3+ ions and characteristic emission peaks from 4f–4f transition of Eu3+ ions. Outstanding temperature-sensing capabilities are acquired from Y4GeO8:Bi3+,Eu3+ phosphor. The maximum relative sensitivity (Sr) can attain 1.51% K−1 (λex = 290 nm). With temperature raising (303–513 K), the emitted color of Y4GeO8:Bi3+,Eu3+ phosphor (λex = 290 nm) shifts from faint yellow to red with a high chromaticity shift (0.180), which can be distinguished by the unaided eye clearly. Our results indicate that Y4GeO8:Bi3+,Eu3+ phosphor has potential applications in optical temperature measurement and high-temperature safety marker. 相似文献