共查询到20条相似文献,搜索用时 15 毫秒
1.
Quanlan Xiao Guoping Dong Jianrong Qiu 《Journal of the American Ceramic Society》2014,97(6):1899-1904
Novel up‐conversion (UC) luminescent nanopowders, Sr2CeO4:Yb3+,Ln3+ (Ln = Er, Tm, Ho) were prepared with Pechini method. The Sr2CeO4:Yb3+,Ln3+ (Ln = Er, Tm, Ho) nanopowders had an orthorhombic crystal structure, and showed olive‐like morphology with the length of about 260 nm and width of about 130 nm. Under 980 nm lazer excitation, the Sr2CeO4:Yb3+/Er3+, Sr2CeO4:Yb3+/Tm3+, and Sr2CeO4:Yb3+/Ho3+ nanophosphors exhibit strong green, blue, and green UC luminescence, respectively. The luminescence mechanisms for the doped lanthanide ions were thoroughly analyzed. 相似文献
2.
《Ceramics International》2016,42(4):4642-4647
Tunable up-conversion luminescent material KY(MoO4)2: Yb3+, Ln3+ (Ln=Er, Tm, Ho) has been synthesized by a typical hydrothermal process. Under 980 nm laser diode (LD) excitation, the emission intensity and the corresponding luminescence colors of KY(MoO4)2: Yb3+, Ln3+ (Ln=Er, Tm, Ho) have been investigated in detail. The energy transfer from the Yb3+ sensitizer to Ho3+, Er3+ and Tm3+ activators plays an important role in the development of color-tunable single- phased phosphors. The emission intensity keep balance through control of the Ho3+ co-doping concentrations, white light was experimentally shown at KY(MoO4)2: 20 mol% Yb3+, 0.8 mol% Er3+, 0.5 mol% Tm3+, 1.0 mol% Ho3+ phosphor with further calcination at 800 °C for 4 h under 980 nm laser excitation. The color tunability, high quality of white light and high intensity of the emitted signal make these up-conversion (UC) phosphors excellent candidates for applications in solid-state lighting. 相似文献
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4.
《Ceramics International》2017,43(8):6333-6339
As alternatives to Yb3+-sensitized up-conversion (UC) materials excited at 980 nm, Nd3+-sensitized UC phosphors irradiated by 808 nm have been used to decrease the absorption of water and alleviate the overheating effect in vivo biological application. Intense red and green UC emissions from 5F5→5I8 and 5F4/5S2→5I8 transitions of Ho3+ appeared in Nd3+/Yb3+/Ho3+ tri-doped NaLa(MoO4)2 through successive energy transfer Nd3+→Yb3+→Ho3+ under 808 nm excitation, in which Yb3+ ions were proven to be the energy transfer bridge between Nd3+ and Ho3+ by lifetime measurement. The variable emission color and intensity ratios of red to green emissions were realized by adjusting the doping concentration of Yb3+, pulse width of the excitation laser and the addition of Ce3+ ion, which depends on the different population pathways to the green and red emitting states of Ho3+. The chromaticity modulation mechanisms of these approaches were proposed, which provides a feasible strategy to tune the UC emission color. 相似文献
5.
Optical Temperature Sensing Behavior of High‐Efficiency Upconversion: Er3+–Yb3+ Co‐Doped NaY(MoO4)2 Phosphor 下载免费PDF全文
Xingxing Yang Zuoling Fu Yanmin Yang Chunpeng Zhang Zhijian Wu Tianqi Sheng 《Journal of the American Ceramic Society》2015,98(8):2595-2600
A class of Yb3+/Er3+ co‐doped NaY(MoO4)2 upconversion (UC) phosphors have been successfully synthesized by a facile hydrothermal route with further calcination. The structural properties and the phase composition of the samples were characterized by X‐ray diffraction (XRD). The UC luminescence properties of Yb3+/Er3+ co‐doped NaY(MoO4)2 were investigated in detail. Concentration‐dependent studies revealed that the optimal composition was realized for a 2% Er3+ and 10% Yb3+‐doping concentration. Two‐photon excitation UC mechanism further illustrated that the green enhancement arised from a novel energy‐transfer (ET) pathway which entailed a strong ground‐state absorption of Yb3+ ions and the excited state absorption of Yb3+–MoO42? dimers, followed by an effective energy transfer to the high‐energy state of Er3+ ions. We have also studied the thermal properties of UC emissions between 303 and 523 K for the optical thermometry behavior under a 980 nm laser diode excitation for the first time. The higher sensitivity for temperature measurement could be obtained compared to the previous reported rare‐earth ions fluorescence based optical temperature sensors. These results indicated that the present sample was a promising candidate for optical temperature sensors with high sensitivity. 相似文献
6.
REVO4‐Based Nanomaterials (RE = Y,La, Gd,and Lu) as Hosts for Yb3+/Ho3+, Yb3+/Er3+, and Yb3+/Tm3+ Ions: Structural and Up‐Conversion Luminescence Studies 下载免费PDF全文
Artur Tymiński Tomasz Grzyb Stefan Lis 《Journal of the American Ceramic Society》2016,99(10):3300-3308
Rare‐earth vanadates of the form REVO4 (RE = Y, La, Gd, and Lu) doped by Yb3+/Ho3+, Yb3+/Er3+, or Yb3+/Tm3+ lanthanide ions were successfully synthesized using the sol–gel method and annealing at 600°C in an air atmosphere. The structure and morphology of the prepared nanocrystals were investigated by X‐ray diffraction, thermogravimetric analysis, transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy. All prepared materials were homogenous and had nanosized dimensions. Their elemental compositions were confirmed by optical emission spectrometry. Spectroscopic analysis of the materials was carried out by measuring excitation and emission spectra, luminescence decays, and dependence between the intensity of the luminescence and the laser energy. Following effective excitation by NIR radiation, Ln3+ co‐doped vanadate matrices exhibited a strong up‐conversion (UC) luminescence. Differences in spectroscopic properties between monoclinic LaVO4 and tetragonal YVO4, GdVO4, or LuVO4 doped by Ln3+ ions were observed, indicating the influence of the crystal structure on the UC emission. Drawing conclusions from these spectroscopic investigations, the UC mechanisms were proposed, including energy‐transfer processes between Yb3+ ions and emitting ions. 相似文献
7.
Jianxiong Zhao Qinyuan Zhang Ni Qin Baojun Li Dinghua Bao 《Journal of the American Ceramic Society》2013,96(4):1214-1219
The color‐tunable up‐conversion (UC) emission and infrared photoluminescence and dielectric relaxation of Er3+/Yb3+ co‐doped Bi2Ti2O7 pyrochlore thin films prepared by a chemical solution deposition method have been investigated. The pyrochlore phase structure of Bi2Ti2O7 can be stabilized by Er3+/Yb3+ co‐doping. Intense color‐tunable UC emission and infrared photoluminescence can be detected on the thin films excited by a 980 nm diode laser. Two UC emission bands centered at 548 and 660 nm in the spectra can be assigned to 2H11/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3+ ions, respectively. A Stokes infrared emission centered at 1530 nm is due to 4I13/2 → 4I15/2 transition of Er3+ ions. The dependence of UC emission intensity on pumping power indicates that the UC emission of the thin films is a two‐photon process. The thin films also exhibit a relatively high dielectric constant and a low dissipation factor as well as a good bias voltage stability. Temperature‐ and frequency‐dependent dielectric relaxation has been confirmed. This study suggests that Er3+/Yb3+ co‐doped Bi2Ti2O7 thin films can be applied to new multifunctional photoluminescence dielectric thin‐film devices. 相似文献
8.
De‐Long Zhang Cong‐Xian Qiu Wen‐Zhu Zhang Ping‐Rang Hua Dao‐Yin Yu Edwin Yue‐Bun Pun 《Journal of the American Ceramic Society》2013,96(11):3476-3482
Co‐diffusion characteristics of Er3+ and Tm3+ ions in LiNbO3 crystal have been studied, together with two other properties: doping effect on refractive index of substrate, and Li out‐diffusion. Er3+/Tm3+‐codoped LiNbO3 single‐crystals were prepared by co‐diffusion of stacked Er‐ and Tm‐metal thin films, coated onto parts of the surfaces of X‐ and Z‐cut congruent LiNbO3 crystal plates, at different temperatures and different durations in air. After diffusion, the surface refractive indices of the doped and undoped parts were measured by prism coupling technique, and the surface composition was evaluated from the measured indices. The results show that the dopings have negligible effect on the substrate index and the Li out‐diffusion depends mainly on the diffusion temperature. The Er3+ and Tm3+ profiles were studied using secondary ion mass spectrometry, and a co‐diffusion dynamical model is proposed and verified experimentally. From the measured profiles, the temperature‐dependent Er3+/Tm3+ diffusivity and solubility were obtained together with other relevant parameters, such as diffusion constant, activation energy, solubility constant and heat of solution. The Er3+ and Tm3+ co‐diffusion exhibits similar temperature dependent diffusivity, and the dependence is similar to that of single‐diffusion. In the co‐diffusion case, the total solubility consists of two parts: Er3+ and Tm3+ parts, there is no anisotropy, and the value is equal to that of single‐diffusion case, in which both ions have the similar solubility. The Er3+ and Tm3+ parts of solubility change relatively with the initial metal film thicknesses and hence have different temperature dependences. Nevertheless, their sum, i.e., the co‐diffusion solubility, remains a constant at a given temperature. 相似文献
9.
Upconversion Luminescence and Energy‐Transfer Mechanism of NaGd(MoO4)2: Yb3+/Er3+ Microcrystals 下载免费PDF全文
Anming Li Dekang Xu Yueli Zhang Hao Lin Shenghong Yang Zhenqiang Chen Yuanzhi Shao 《Journal of the American Ceramic Society》2016,99(5):1657-1663
Uniform and well‐crystallized NaGd(MoO4)2: Yb3+/Er3 + microcrystals with tetragonal plate morphology were synthesized by a facile hydrothermal method. The structure and phase purity of the samples were identified by powder XRD analysis. The steady‐state and transient luminescence spectra were measured and analyzed. Under 980 nm excitation, intense green luminescence at 531 and 553 nm, and red luminescence at 657 and 670 nm were observed. The optimum doping concentrations for Yb3+ and Er3+ are determined to be 20% and 1% in NaGd(MoO4)2 tetragonal plate microcrystals. With increasing Yb3+ doping concentrations, the total integral emission intensities increase first and then decrease. The red/green intensity ratio of NaGd(MoO4)2: Yb3+/Er3+ microcrystals increases from 0.4 to 1.0 with the increase in Yb3+ concentrations. Based on the energy level diagram, the energy‐transfer mechanisms are investigated in detail according to the double logarithmic plot of upconversion intensities versus pump powers. The energy‐transfer mechanisms for green and red upconversion luminescence are ascribed to two‐photon processes at lower Yb3+ concentrations, and involve high‐Yb3+‐induced one‐photon processes at higher Yb3+ concentrations. For the red upconversion luminescence, energy back‐transfer process, that is, 4S3/2 (Er3+) + 2F7/2 (Yb3+) → 4I13/2 (Er3+) + 2F5/2 (Yb3+), is dominant at higher Yb3+ concentrations. Theoretical model of the energy‐transfer mechanisms based on rate equations is established, which agrees well with the experimental results. 相似文献
10.
采用水热法制备了掺杂不同比例Ho3 +/Tmn3+和不同Ylb3+浓度的NaGdF4∶Ho3+,Tm3+,Yb3+上转换发光粉,对其结构和上转换发光性能进行了表征.XRD研究结果表明:所有的样品均为六方结构NaGdF4.980 nm红外光激发下,稀土掺杂的NaGdF4发光粉显示分别来自于Ho3+离子5S2,5F4(Ho)→5I8 (Ho)跃迁发射的绿光,5F5 (Ho)→5I8(Ho)跃迁发射的红光,5 S2,5 F4(Ho)→5I7(Ho)跃迁发射的近红外光;来自Tm3+离子1D2(Tm)→3F4(Tm)和1 G4(Tm)→3H6 (Tm)跃迁发射的蓝光,1 G4(Tm)→3 F4(Tm)跃迁发射的红光,3H4(Tm) →3 H6 (Tm)跃迁发射的红外光.研究了Ho3 +/Tm3比例和Yb3+浓度对发光粉上转换发光性能的影响,并讨论了体系的上转换发光机制.计算的发光粉色坐标显示:掺杂Ho3 +/Tm3+比例和Yb3+浓度的变化能调控样品上转换发光颜色. 相似文献
11.
Ho3+/Yb3+‐codoped Bi2Ti2O7 pyrochlore thin films were prepared by a chemical solution deposition method, and their visible up‐conversion (UC) photoluminescence and dielectric relaxation were studied. Ho and Yb can be doped into Bi2Ti2O7 lattice and single pyrochlore phase is maintained. Intense visible UC photoluminescence can be observed under the excitation of a 980‐nm diode laser. Two UC emission bands centered at 551 nm and 665 nm in the spectra can be assigned to 5F4, 5S2→5I8 and 5F5→5I8 transitions of Ho3+ ions, respectively. The dependence of their UC emission intensity on pumping power indicates that both the green and red emissions of the thin films are two‐photon process. In addition, a Stokes near‐infrared emission centered at 1200 nm can be detected, which is due to 5I6→5I8 transition of Ho3+ ions. The thin films prepared on indium tin oxide–coated glass substrates exhibit a relatively high dielectric constant and a low dielectric loss as well as a good bias voltage stability. The dielectric relaxation of the thin films was also analyzed based on the temperature‐ and frequency‐dependent dielectric properties. This study suggests that Ho3+/Yb3+‐codoped Bi2Ti2O7 thin films are promising materials for developing multifunctional optoelectronic thin film devices. 相似文献
13.
Preparation,Structure, and Up‐Conversion Luminescence of Yb3+/Er3+ Codoped SrIn2O4 Phosphors 下载免费PDF全文
Ming Guan Hong Zheng Lefu Mei Maxim S. Molokeev Jing Xie Tao Yang Xiaowen Wu Saifang Huang Zhaohui Huang 《Journal of the American Ceramic Society》2015,98(4):1182-1187
SrIn2O4, which shows lower phonon energy than CaIn2O4, is not only a good photocatalyst but also can be an excellent up‐conversion (UC) host to exhibits UC luminescence. In this work, Yb3+ and/or Er3+ doped SrIn2O4 phosphors were synthesized, and their UC luminescence properties were studied and compared with those in the CaIn2O4 host. The structure of SrIn2O4: 0.01Er3+ and SrIn2O4: 0.1Yb3+/0.01Er3+ samples were refined by the Rietveld method and found to that SrIn2O4: 0.1Yb3+/0.01Er3+ showed increasing unit cell parameters and cell volume, indicating In3+ sites were substituted successfully by Yb3+ and/or Er3+ ions. From the UC luminescence spectra and diffuse reflection spectra, Er3+‐doped SrIn2O4 showed very weak luminescence due to ground state absorption of Er3+; Yb3+/Er3+ codoped SrIn2O4 presented strong green (550 nm) and red (663 nm) UC emissions which were assigned to energy transfer from Yb3+ transition 2F7/2→2F5/2 to the Er3+ transition 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2. Comparing with CaIn2O4, Yb3+/Er3+ codoped SrIn2O4 showed obvious advantages with higher UC luminescent intensity. The pumping powers study showed that UC emissions in Yb3+/Er3+ codoped SrIn2O4 were attributed to energy transfer of Yb3+→Er3+ with a two‐photon process. The possible UC luminescent mechanism of Yb3+/Er3+‐doped SrIn2O4 was discussed. 相似文献
14.
采用凝胶-燃烧法合成了LiLa(MoO4)2:Dy3+黄色荧光粉,借助XRD、FE-SEM、荧光光谱仪对样品的晶体结构、形貌、发光特性等进行了分析.结果表明:所得LiLa(MoO4)2:Dy3+样品为四方白钨矿型结构,平均粒径为500 nm左右;样品的发射光谱由位于486 nm较强的蓝光发射、574 nm很强的黄光发射和662 nm较弱的红光发射组成,CIE1931色坐标为(0.3848,0.4341),位于黄光区;Dy3+最佳掺杂量为x=0.025 mol;柠檬酸的最佳加入量为n(NO3-)/n(C6H8O7)=3.0;最佳点火温度为650℃. 相似文献
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Intense upconversion luminescence and energy‐transfer mechanism of Ho3+/Yb3+ co‐doped SrLu2O4 phosphor 下载免费PDF全文
Songbin Liu Xinyu Ye Shuifu Liu Mengyao Chen Hu Niu Dejian Hou Weixiong You 《Journal of the American Ceramic Society》2017,100(8):3530-3539
A series of novel SrLu2O4: x Ho3+, y Yb3+ phosphors (x=0.005‐0.05, y=0.1‐0.6) were synthesized by a simple solid‐state reaction method. The phase purity, morphology, and upconversion luminescence were measured by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy. The doping concentrations and sintering temperature were optimized to be x=0.01, y=0.5 and T=1400°C to obtain the strongest emission intensity. Under 980 nm laser diode excitation, the SrLu2O4:Ho3+, Yb3+ phosphors exhibit intense green upconversion (UC) emission band centered at 541 nm (5F4,5S2→5I8) and weak red emission peaked at 673 nm (5F5→5I8). Under different pump‐power excitation, the UC luminescence can be finely tuned from yellow‐green to green light region to some extent. Based on energy level diagram, the energy‐transfer mechanisms are investigated in detail according to the analysis of pump‐power dependence and luminescence decay curves. The energy‐transfer mechanisms for green and red UC emissions can be determined to be two‐photon absorption processes. Compared with commercial NaYF4:Er3+, Yb3+ and common Y2O3:Ho3+, Yb3+ phosphors, the SrLu1.49Ho0.01Yb0.5O4 sample shows good color monochromaticity and relatively high UC luminescence intensity. The results imply that SrLu2O4:Ho3+, Yb3+ can be a good candidate for green UC material in display fields. 相似文献
16.
Transmission electron microscopic and optical spectroscopic studies of Ni2+/Yb3+/Er3+/Tm3+ doped dual‐phase glass‐ceramics 下载免费PDF全文
Zhigang Gao Xiaosong Lu Yindong Zhang Shu Guo Yinyao Liu Shiyu Sun Fei He Piaoping Yang Jing Ren Jun Yang 《Journal of the American Ceramic Society》2018,101(7):2868-2876
Ni2+/Yb3+/Er3+/Tm3+ codoped transparent glass‐ceramics (GCs) containing both hexagonal β‐YF3 and spinel‐like γ‐Ga2O3 dual‐phase nanoparticles (NCs) are synthesized by melt‐quenching and subsequent heating procedures. Two techniques of transmission electron microscopy (TEM) nanoanalytics and optical spectroscopy are conjugated to understand the distribution of the rare‐earth ions (REs) and transition metals (TMs) in the nanostructured GCs. It is found that the REs are located predominantly in β‐YF3, whereas the TMs in γ‐Ga2O3 NCs. As a result, energy transfer (ET) between the REs and TMs is considerably suppressed due to the large spatial separation (> 3 nm), but it is enhanced between the REs partitioned in the β‐YF3 NCs. This has important implications for intended and demanding photoluminescence functions. For example, an ultrabroadband near‐infrared (NIR) emission in the wavelength region of 1000‐2000 nm covering the entire telecommunications window is observed for the first time. Meanwhile, intense upconversion (UC) emissions covering the 3 primary colors and locating in the first biological window can be also recorded under excitation by a single pump source at 980 nm. 相似文献
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稀土Tm3+和敏化剂(Yb3+)共掺NaYF4是目前发现的Tm3+上转换发光效率最高的材料,但还不能满足实际应用.实验中采用Sc3+/Tm3+/Yb3+共掺Na(Y1-x-y,Tmx,Yby)F4研究不同掺量Sc3+对Tm3+上转换发光效率的影响.用X射线多晶衍射仪和透射电子显微镜分析水热法合成样品的物相结构和晶粒尺寸... 相似文献
18.
Microwave Sol–Gel Synthesis of CaGd2(MoO4)4:Er3+/Yb3+ Phosphors and Their Upconversion Photoluminescence Properties 下载免费PDF全文
Chang Sung Lim Victor Atuchin Aleksandr Aleksandrovsky Maxim Molokeev Aleksandr Oreshonkov 《Journal of the American Ceramic Society》2015,98(10):3223-3230
CaGd2(MoO4)4:Er3+/Yb3+ phosphors with the doping concentrations of Er3+ and Yb3+ (x = Er3+ + Yb3+, Er3+ = 0.05, 0.1, 0.2, and Yb3+ = 0.2, 0.45) have been successfully synthesized by the microwave sol–gel method, and the crystal structure refinement and upconversion photoluminescence properties have been investigated. The synthesized particles, being formed after heat‐treatment at 900°C for 16 h, showed a well‐crystallized morphology. Under the excitation at 980 nm, CaGd2(MoO4)4:Er3+/Yb3+ particles exhibited strong 525 and 550‐nm emission bands in the green region and a weak 655‐nm emission band in the red region. The Raman spectrum of undoped CaGd2(MoO4)4 revealed about 15 narrow lines. The strongest band observed at 903 cm?1 was assigned to the ν1 symmetric stretching vibration of MoO4 tetrahedrons. The spectra of the samples doped with Er and Yb obtained under 514.5 nm excitation were dominated by Er3+ luminescence preventing the recording Raman spectra of these samples. Concentration quenching of the erbium luminescence at 2H11/2→4I15/2 and 4S3/2→4I15/2 transitions in the CaGd2(MoO4)4:Er3+/Yb3+ crystal structure was established to be approximately at the 10 at.% doping level. 相似文献
19.
Highly Sensitive Optical Thermometry of Yb3+‐Er3+ Codoped AgLa(MoO4)2 Green Upconversion Phosphor 下载免费PDF全文
Ting Li Chongfeng Guo Shaoshuai Zhou Changkui Duan Min Yin 《Journal of the American Ceramic Society》2015,98(9):2812-2816
Er3+–Yb3+ codoped AgLa(MoO4)2 phosphors with intense green emission from 2H11/2/4S3/2 → 4I15/2 transitions and negligible red emission from 4F9/2 → 4I15/2 transition of Er3+ were synthesized by sol–gel process. Its temperature sensing performance was evaluated based on the temperature dependence of fluorescence intensity ratio (FIR) of two green emission bands in the range 300–510 K. The maximum sensitivity of AgLa(MoO4)2: 0.02Er3+/0.4Yb3+ is approximately 0.018 K?1 at 480 K, which is much higher than those of reported samples based on green emissions of Er3+. Result suggests that AgLa(MoO4)2: Er3+/Yb3+ has a great potential application in optical temperature sensors. 相似文献
20.
Dongyu Li Weijiang Xu Zhen Huang Xiao Jin Bing Xu Zhenghe Zhang Tingting Zhang Deng Wang Xuping Liu Hao Suo Qinghua Li 《Journal of the American Ceramic Society》2023,106(1):438-447
The effects of site symmetric distortion induced by the phase transition on up-conversion emission and thermal sensing performance of Gd2(MoO4)3:Yb3+/Er3+ (GMO) crystals were elaborately studied by minimizing interference from many factors. Monoclinic GMO showed a much stronger fluorescence intensity and larger fluorescence intensity ratio under the irradiation of 980 nm laser in comparison to the orthorhombic counterpart. These remarkable up-conversion properties stemmed from the low site symmetry with large site symmetric distortion in monoclinic GMO. Moreover, the thermal sensing property of the samples was assessed based on the fluorescence intensity ratio technique, where monoclinic GMO exhibited much higher maximum absolute sensitivity (Sa = 0.0257 K−1 at 510 K) due to the site symmetric distortion, which was further explained by the Judd–Ofelt theory and polarizability of the chemical bond volume model. Results opened an efficient avenue for achieving highly sensitive thermometry in many daily scenarios via finely tailoring the local site symmetry. 相似文献