Lu3Al5O12 single crystals grown in pure N2 atmosphere by Czochralski method were annealed in oxidizing atmosphere （air）and reducing atmosphere （H2 ＋ N2）, respectively. Effects of annealing treatments on luminesce...Lu3Al5O12 single crystals grown in pure N2 atmosphere by Czochralski method were annealed in oxidizing atmosphere （air）and reducing atmosphere （H2 ＋ N2）, respectively. Effects of annealing treatments on luminescence and scintillation properties of the crystals were investigated. The crystal annealed in air showed the highest luminescence intensity under blue light or vacuum ultraviolet excitation in comparison with that annealed in reducing flux or the as-grown crystal. Under X-ray excitation, crystal annealed in reducing atmosphere had the lowest light yield, and crystal annealed in air had the fastest decay time under ^137Cs 662 keV γ-ray excitation. Different annealing treatments resulted in different luminescence and scintillation properties, which might related with oxygen vacancies or defect existing in the crystals.展开更多
Lutetium aluminum garnet （LuAG） precursors doped with different Pr^3＋ concentration （0.25at.%, 0.5at.%, 1.0at.%, 3.0at.%, 5.0at.%） were synthesized via a co-precipitation method using ammonium hydrogen carbonate ...Lutetium aluminum garnet （LuAG） precursors doped with different Pr^3＋ concentration （0.25at.%, 0.5at.%, 1.0at.%, 3.0at.%, 5.0at.%） were synthesized via a co-precipitation method using ammonium hydrogen carbonate as precipitant. The phase evolution and morphology of the precursor were characterized with X-ray diffractometer （XRD） and transmission electron microscopy （TEM）. The resultant LuAG：Pr^3＋ powder was sintered into translucent ceramic without any additives in vacuum at 1150 ℃ and then in nitrogen atmosphere at 1700 ℃. spectra of LuAG：Pr^3＋ powder and ceramic were measured at room temperature in vacuum ultraviolet （VUV） and ultraviolet （VU） region. For the 5d-4f transition of Pr^3＋ ions, dominant emission of ceramic samples peaking round 311 um had higher luminescence intensity. And the host absorption in ceramic samples was not as intensive as that in powder samples. The luminescent intensity of LuAG：Pr^3＋ varied with the Pr^3＋ contents and the quenching concentration was about 1.0at.% for ceramic and 3.0at.% for powder, which was much higher than 0.24at.% for LuAG：Pr^3＋ single crystals. This phenomenon showed that the ceramic had some superiority over single crystals.展开更多
实现高发光效率、高亮度和良好的热稳定性是固态照明的迫切要求。因此,用于高功率发光二极管或激光二极管(LED/LD)的高性能荧光转换材料具有重要的研究意义。在这项工作中,通过将Lu^(3+)离子引入YAG∶Ce荧光陶瓷中方法作为有效策略来改...实现高发光效率、高亮度和良好的热稳定性是固态照明的迫切要求。因此,用于高功率发光二极管或激光二极管(LED/LD)的高性能荧光转换材料具有重要的研究意义。在这项工作中,通过将Lu^(3+)离子引入YAG∶Ce荧光陶瓷中方法作为有效策略来改善YAG∶Ce荧光材料的发光性能。采用固相反应和真空烧结法制Article ID:1000-7032(2023)06-0964^(-1)1收稿日期:2022^(-1)2-31;修订日期:2023-01-30基金项目:中国科学院战略性先导科技专项(XDA22010301)Supported by The Strategic Priority Research Program of The Chinese Academy of Sciences(XDA22010301)第6 HUANG Xinyou期,et al.:LuYAG∶Ce Transparent Ceramic Phosphors for High-brightness Solid-state…备了不同Lu^(3+)含量的(Lu,Y)_(3)Al_(5)O_(12)∶Ce荧光陶瓷(LuYAG∶Ce荧光陶瓷)。随着Lu^(3+)含量的增加,LuYAG∶Ce荧光陶瓷中的Y^(3+)位点被Lu^(3+)位点取代,Ce^(3+)的发射峰呈现从573 nm到563 nm的蓝移现象。当Lu^(3+)含量为60%时,通过将LuYAG∶Ce荧光陶瓷与蓝光LED组合,其发光强度达到最大值,流明效率达到114 lm∙W^(-1)。使用450 nm激光源与LuYAG∶Ce荧光陶瓷构建了透射模式下的激光驱动照明装置。随着功率密度从2.2 W·mm^(-2)增加到39 W·mm^(-2),Lu^(3+)含量为60%的荧光陶瓷光通量从128 lm增加到1874 lm,且没有发光饱和的迹象,最佳发光效率达到128 lm·W^(-1)。因此,LuYAG∶Ce荧光陶瓷有望成为高功率LED/LD照明的潜在荧光转换材料。展开更多
A kind of optical data storage medium based on electron-trapping materials,Y_(3)Al_(5)O_(12):Ce^(3+)fluorescent ceramic,was developed by vacuum sintering technology.The medium shows sufficiently deep traps[1.67 and 0....A kind of optical data storage medium based on electron-trapping materials,Y_(3)Al_(5)O_(12):Ce^(3+)fluorescent ceramic,was developed by vacuum sintering technology.The medium shows sufficiently deep traps[1.67 and 0.77 eV].The properties of trap levels were researched by thermoluminescence curves,and the optical storage mechanism based on Ce^(3+)ion doping was proposed.More importantly,the data can be written-in by 254 nm UV light,and readout by heating[300°C].This work expands the application fields of fluorescent ceramics,and it is expected to promote the development of electron-trapping materials.展开更多
Ytterbium aluminum garnet(Yb3Al5O12)is considered as a promising thermal barrier material.However,the main limitations of Yb3Al5O12 for thermal barrier applications are relative low thermal expansion coefficient and h...Ytterbium aluminum garnet(Yb3Al5O12)is considered as a promising thermal barrier material.However,the main limitations of Yb3Al5O12 for thermal barrier applications are relative low thermal expansion coefficient and high thermal conductivity.In order to overcome these obstacles,herein,a new high entropy(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 ceramic was designed,and then powders and bulk were prepared through solid-state reaction method and spark plasma sintering(SPS),respectively.The thermal expansion coefficient of HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 is(8.54±0.29)×10^-6 K^-1 at 673 K–1273 K,which is about 9%higher than that of Yb3Al5O12.The thermal conductivity of HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 ceramic is 3.81 W·m^-1 K^-1 at 300 K,which is about 18%lower than that of Yb3Al5O12.Moreover,there is no reaction between HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 and thermally grown(TG)Al2O3 even at 1600℃.After annealing at 1590℃for 18 h,the average grain size of HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 increases only from 1.56μm to 2.27μm.Close thermal expansion coefficient to TG Al2O3,low thermal conductivity,good phase stability,excellent chemical compatibility with TG Al2O3 and slow grain growth rate make HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 promising for thermal barrier applications.展开更多
In this paper,a novel Ce(Gd2 Y)Al5O12/Ce:Y3Al5O12(Ce:GYAG/Ce:YAG)composite scintillation ceramic was designed and fabricated by a solid-state reaction method.The phase,luminescence and scintillation properties were in...In this paper,a novel Ce(Gd2 Y)Al5O12/Ce:Y3Al5O12(Ce:GYAG/Ce:YAG)composite scintillation ceramic was designed and fabricated by a solid-state reaction method.The phase,luminescence and scintillation properties were investigated.The Ce:GYAG/Ce:YAG composite ceramic consisting of two-phase has a broad emission band ranging from 500 to 750 nm.The total mass attenuation coefficient of Ce:GYAG/Ce:YAG is 0.3864 cm^-1,in between those of Ce:YAG and Ce:GYAG ceramics.In addition,the composite ceramic had a high light yield of 20430 ph/MeV.By controlling the ratio of GYAG and YAG,the composite ceramic can realize a spectrum design and total mass attenuation coefficient control to meet the requirements for wide-X-ray-energy-range detectors.展开更多
Pulling growth technique serves as a popular method to grow congruent melting single crystals with multiscale sizes ranging from micrometers to centimeters.In order to obtain high quality single crystals,the crystal c...Pulling growth technique serves as a popular method to grow congruent melting single crystals with multiscale sizes ranging from micrometers to centimeters.In order to obtain high quality single crystals,the crystal constituents would be arranged at the lattice sites by precisely controlling the crystal growth process.Growing interface is the position where the phase transition of crystal constituents occurs during pulling growth process.The precise control of energy at the growing interface becomes a key technique in pulling growth.In this work,we review some recent advances of pulling technique towards rare earth single crystal growth.In Czochralski pulling growth,the optimized growth parameters were designed for rare earth ions doped Y_3Al_5O_(12)and Ce:(Lu_(1-x)Y_x)_2Si O_5on the basis of anisotropic chemical bonding and isotropic mass transfer calculations at the growing interface.The fast growth of high quality rare earth single crystals is realized by controlling crystallization thermodynamics and kinetics in different size zones.On the other hand,the micro pulling down technique can be used for high throughput screening novel rare earth optical crystals.The growth interface control is realized by improving the crucible bottom and temperature field,which favors the growth of rare earth crystal fibers.The rare earth laser crystal fiber can serve as another kind of laser gain medium between conventional bulk single crystal and glass fiber.The future work on pulling technique might focus on the mass production of rare earth single crystals with extreme size and with the size near that of devices.展开更多
基金Project supported by the National Natural Science Foundation of China (20571088)the Science and Technology Project of Guangdong Province (2005B10301016, 2006B14801001)
文摘Lu3Al5O12 single crystals grown in pure N2 atmosphere by Czochralski method were annealed in oxidizing atmosphere （air）and reducing atmosphere （H2 ＋ N2）, respectively. Effects of annealing treatments on luminescence and scintillation properties of the crystals were investigated. The crystal annealed in air showed the highest luminescence intensity under blue light or vacuum ultraviolet excitation in comparison with that annealed in reducing flux or the as-grown crystal. Under X-ray excitation, crystal annealed in reducing atmosphere had the lowest light yield, and crystal annealed in air had the fastest decay time under ^137Cs 662 keV γ-ray excitation. Different annealing treatments resulted in different luminescence and scintillation properties, which might related with oxygen vacancies or defect existing in the crystals.
基金supported by the National Natural Science Foundation of China (10774140)Funds for International Cooperation and Exchange of the National Nature Science Foundation of China (50711120504)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education (20060358054)Special Foundation for Talents of Anhui Province, China (2007Z021)
文摘Lutetium aluminum garnet （LuAG） precursors doped with different Pr^3＋ concentration （0.25at.%, 0.5at.%, 1.0at.%, 3.0at.%, 5.0at.%） were synthesized via a co-precipitation method using ammonium hydrogen carbonate as precipitant. The phase evolution and morphology of the precursor were characterized with X-ray diffractometer （XRD） and transmission electron microscopy （TEM）. The resultant LuAG：Pr^3＋ powder was sintered into translucent ceramic without any additives in vacuum at 1150 ℃ and then in nitrogen atmosphere at 1700 ℃. spectra of LuAG：Pr^3＋ powder and ceramic were measured at room temperature in vacuum ultraviolet （VUV） and ultraviolet （VU） region. For the 5d-4f transition of Pr^3＋ ions, dominant emission of ceramic samples peaking round 311 um had higher luminescence intensity. And the host absorption in ceramic samples was not as intensive as that in powder samples. The luminescent intensity of LuAG：Pr^3＋ varied with the Pr^3＋ contents and the quenching concentration was about 1.0at.% for ceramic and 3.0at.% for powder, which was much higher than 0.24at.% for LuAG：Pr^3＋ single crystals. This phenomenon showed that the ceramic had some superiority over single crystals.
文摘实现高发光效率、高亮度和良好的热稳定性是固态照明的迫切要求。因此,用于高功率发光二极管或激光二极管(LED/LD)的高性能荧光转换材料具有重要的研究意义。在这项工作中,通过将Lu^(3+)离子引入YAG∶Ce荧光陶瓷中方法作为有效策略来改善YAG∶Ce荧光材料的发光性能。采用固相反应和真空烧结法制Article ID:1000-7032(2023)06-0964^(-1)1收稿日期:2022^(-1)2-31;修订日期:2023-01-30基金项目:中国科学院战略性先导科技专项(XDA22010301)Supported by The Strategic Priority Research Program of The Chinese Academy of Sciences(XDA22010301)第6 HUANG Xinyou期,et al.:LuYAG∶Ce Transparent Ceramic Phosphors for High-brightness Solid-state…备了不同Lu^(3+)含量的(Lu,Y)_(3)Al_(5)O_(12)∶Ce荧光陶瓷(LuYAG∶Ce荧光陶瓷)。随着Lu^(3+)含量的增加,LuYAG∶Ce荧光陶瓷中的Y^(3+)位点被Lu^(3+)位点取代,Ce^(3+)的发射峰呈现从573 nm到563 nm的蓝移现象。当Lu^(3+)含量为60%时,通过将LuYAG∶Ce荧光陶瓷与蓝光LED组合,其发光强度达到最大值,流明效率达到114 lm∙W^(-1)。使用450 nm激光源与LuYAG∶Ce荧光陶瓷构建了透射模式下的激光驱动照明装置。随着功率密度从2.2 W·mm^(-2)增加到39 W·mm^(-2),Lu^(3+)含量为60%的荧光陶瓷光通量从128 lm增加到1874 lm,且没有发光饱和的迹象,最佳发光效率达到128 lm·W^(-1)。因此,LuYAG∶Ce荧光陶瓷有望成为高功率LED/LD照明的潜在荧光转换材料。
基金supported by the National Key Research and Development Program of China(No.2021YFB2802001)the National Natural Science Foundation of China(No.62175153)。
文摘A kind of optical data storage medium based on electron-trapping materials,Y_(3)Al_(5)O_(12):Ce^(3+)fluorescent ceramic,was developed by vacuum sintering technology.The medium shows sufficiently deep traps[1.67 and 0.77 eV].The properties of trap levels were researched by thermoluminescence curves,and the optical storage mechanism based on Ce^(3+)ion doping was proposed.More importantly,the data can be written-in by 254 nm UV light,and readout by heating[300°C].This work expands the application fields of fluorescent ceramics,and it is expected to promote the development of electron-trapping materials.
基金financial supported by the National Natural Science Foundation of China(Nos.51672064 and U1435206)。
文摘Ytterbium aluminum garnet(Yb3Al5O12)is considered as a promising thermal barrier material.However,the main limitations of Yb3Al5O12 for thermal barrier applications are relative low thermal expansion coefficient and high thermal conductivity.In order to overcome these obstacles,herein,a new high entropy(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 ceramic was designed,and then powders and bulk were prepared through solid-state reaction method and spark plasma sintering(SPS),respectively.The thermal expansion coefficient of HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 is(8.54±0.29)×10^-6 K^-1 at 673 K–1273 K,which is about 9%higher than that of Yb3Al5O12.The thermal conductivity of HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 ceramic is 3.81 W·m^-1 K^-1 at 300 K,which is about 18%lower than that of Yb3Al5O12.Moreover,there is no reaction between HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 and thermally grown(TG)Al2O3 even at 1600℃.After annealing at 1590℃for 18 h,the average grain size of HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 increases only from 1.56μm to 2.27μm.Close thermal expansion coefficient to TG Al2O3,low thermal conductivity,good phase stability,excellent chemical compatibility with TG Al2O3 and slow grain growth rate make HE(Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 promising for thermal barrier applications.
基金financially supported by the National Natural Science Foundation of China(Nos.61378069,61405221,and 11535010)Youth Innovation Promotion Association of the Chinese Academy of Science(CAS)+2 种基金National Key Research and Development Program of China(SQ2017YFGX010025-03)Interdisciplinary Innovation Team of the CASGeneral Financial Grant from the China Postdoctoral Science Foundation(No.2016M601654)
文摘In this paper,a novel Ce(Gd2 Y)Al5O12/Ce:Y3Al5O12(Ce:GYAG/Ce:YAG)composite scintillation ceramic was designed and fabricated by a solid-state reaction method.The phase,luminescence and scintillation properties were investigated.The Ce:GYAG/Ce:YAG composite ceramic consisting of two-phase has a broad emission band ranging from 500 to 750 nm.The total mass attenuation coefficient of Ce:GYAG/Ce:YAG is 0.3864 cm^-1,in between those of Ce:YAG and Ce:GYAG ceramics.In addition,the composite ceramic had a high light yield of 20430 ph/MeV.By controlling the ratio of GYAG and YAG,the composite ceramic can realize a spectrum design and total mass attenuation coefficient control to meet the requirements for wide-X-ray-energy-range detectors.
基金supported by Jilin Province Science and Technology Development Project(Grant No.21521092JH)
文摘Pulling growth technique serves as a popular method to grow congruent melting single crystals with multiscale sizes ranging from micrometers to centimeters.In order to obtain high quality single crystals,the crystal constituents would be arranged at the lattice sites by precisely controlling the crystal growth process.Growing interface is the position where the phase transition of crystal constituents occurs during pulling growth process.The precise control of energy at the growing interface becomes a key technique in pulling growth.In this work,we review some recent advances of pulling technique towards rare earth single crystal growth.In Czochralski pulling growth,the optimized growth parameters were designed for rare earth ions doped Y_3Al_5O_(12)and Ce:(Lu_(1-x)Y_x)_2Si O_5on the basis of anisotropic chemical bonding and isotropic mass transfer calculations at the growing interface.The fast growth of high quality rare earth single crystals is realized by controlling crystallization thermodynamics and kinetics in different size zones.On the other hand,the micro pulling down technique can be used for high throughput screening novel rare earth optical crystals.The growth interface control is realized by improving the crucible bottom and temperature field,which favors the growth of rare earth crystal fibers.The rare earth laser crystal fiber can serve as another kind of laser gain medium between conventional bulk single crystal and glass fiber.The future work on pulling technique might focus on the mass production of rare earth single crystals with extreme size and with the size near that of devices.
