This paper reports that the Tm^3＋：Lu2SiO5 （Tm：LSO） crystal is grown by Czochralski technique. The roomtemperature absorption spectra of Tm：LSO crystal are measured on a b-cut sample with 4 at.% thulium. Accordin...This paper reports that the Tm^3＋：Lu2SiO5 （Tm：LSO） crystal is grown by Czochralski technique. The roomtemperature absorption spectra of Tm：LSO crystal are measured on a b-cut sample with 4 at.% thulium. According to the obtained Judd-Ofelt intensity parameters Ω2=9.3155×10^-20 cm^2, Ω4=8.4103×10^-20 cm^2, Ω6=1.5908×10^-20 cm^2, the fluorescence lifetime is calculated to be 2.03 ms for ^3F4 → ^3H6 transition, and the integrated emission cross section is 5.81×10^-18 cm^2. Room-temperature laser action near 2μm under diode pumping is experimentally evaluated in Tm：LSO. An optical-optical conversion efficiency of 9.1% and a slope efficiency of 16.2% are obtained with continuouswave maximum output power of 0.67 W. The emission wavelengths of Tm：LSO laser are centred around 2.06μm with spectral bandwidth of -13.6 nm.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
Sr3SiO5:Eu2+ yellow phosphors for white LEDs were synthesized by high temperature solid state reaction method under a reductive atmosphere. The crystalline phases were examined with X-ray diffraction (XRD). Luminescen...Sr3SiO5:Eu2+ yellow phosphors for white LEDs were synthesized by high temperature solid state reaction method under a reductive atmosphere. The crystalline phases were examined with X-ray diffraction (XRD). Luminescence properties were studied, and effects of various fluxing agents BaCl2, MgF2, CaF2 and BaF2 on the emission spectra were also studied. The optimal Eu2+ concentration and flux were determined. Sr3SiO5: Eu2+ was obtained by firing the sample on optimal composition and fabrication process. The sa...展开更多
A systematical exploration of energy transfer processes in Lu2（1-x）Y2xSiO5：Ce（LYSO） crystals under vacuum ultraviolet-ultraviolet（VUV-UV） excitation was implemented. The relationship between energy transfer and...A systematical exploration of energy transfer processes in Lu2（1-x）Y2xSiO5：Ce（LYSO） crystals under vacuum ultraviolet-ultraviolet（VUV-UV） excitation was implemented. The relationship between energy transfer and scintillation properties was established. It is revealed that there are mainly three energy transfer types in the crystal i.e. host → Ce1/Ce2/STEs, Ce1 →Ce2 and STEs → Ce1/Ce2. The influence of Y content of the LYSO crystals on the energy transfer efficiency of the above processes was carefully analyzed. Besides, we find a special component of the crystal i.e. Y content = 45 at% at which the energy resolution and light output of the crystal perform the worst.展开更多
A novel single-phase Sm^3+activated Ca5(PO4)2SiO4 phosphor was successfully fabricated via a conventional solid-state method,which can be e fficie ntly excited by near ultraviolet(n-UV)light-emitting chips.The crystal...A novel single-phase Sm^3+activated Ca5(PO4)2SiO4 phosphor was successfully fabricated via a conventional solid-state method,which can be e fficie ntly excited by near ultraviolet(n-UV)light-emitting chips.The crystal structure and luminescence properties were characterized and analyzed systematically by using relevant instruments.The Ca5(PO4)2SiO4:Sm^3+phosphor shows an orange-red emission peaking at600 nm under the excitation of 403 nm and the optimal doping concentration of Sm^3+is determined to be 0.08,The critical distance of Ca5(PO4)2SiO4:0.08 Sm^3+is calculated to be 1.849 nm and concentration quenching mechanism of the Sm^3+in Ca5(PO4)2SiO4 host is ascribed to energy transfer between nearestneighbor activators.The decay time of Ca5(PO4)2 SiO4:0,08 Sm^3+is determined to be 1.1957 ms.In addition,the effect of temperature on the emission intensity was also studied,72.4%of the initial intensity is still preserved at 250℃,better thermal stability compared to commercial phosphor YAG:Ce^3+indicates that Ca5(PO4)2SiO4:0.08 Sm^3+has excellent thermal stability and active energy is deduced to be 0.130 eV.All the results demonstrate that orange-red emitting Ca5(PO4)2SiO4:0.08 Sm3+phosphor exhibits good luminescent properties.Owing to the excellent thermal quenching luminescence property,Ca5(PO4)2SiO4:0.08 Sm^3+phosphor can be applied in n-UV white light emitting diodes and serve as the warm part of white light.展开更多
Undoped LaAlO3 and 1 at.%Ce:LaAlO3 single crystals were grown by the Czochralski process.Absorption and fluorescence spectra were measured at room temperature.Detailed energy levels structure of Ce:LaAlO3 was determin...Undoped LaAlO3 and 1 at.%Ce:LaAlO3 single crystals were grown by the Czochralski process.Absorption and fluorescence spectra were measured at room temperature.Detailed energy levels structure of Ce:LaAlO3 was determined.In this paper,two viewpoints were provided.The first one is:the energy levels structure of Ce:LaAlO3 is very similar to that of Ce:Lu2(SiO4)O which is a well-known scintillator.In the energy levels structure of Ce:LaAlO3 and Ce:Lu2(SiO4)O,the lowest 5d energy level of Ce 3+ is located below the bottom of the conduction band of host crystal and the other higher 5d energy levels of Ce 3+ are located above the bottom of the conduction band of host crystal.The second one is:Ce:LaAlO3 single crystal may not be suitable for scintillation application;by comparing the energy levels structures of Ce:LaAlO3 and Ce:Lu2(SiO4)O,the large energy difference(1.13 eV)between the two lowest 5d energy levels of Ce 3+ in LaAlO3 is a crucial factor that causes the luminescence quenching.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 Program of Excellent Team in Harbin Institute of Technology, China (Grant No 60878011)
文摘This paper reports that the Tm^3＋：Lu2SiO5 （Tm：LSO） crystal is grown by Czochralski technique. The roomtemperature absorption spectra of Tm：LSO crystal are measured on a b-cut sample with 4 at.% thulium. According to the obtained Judd-Ofelt intensity parameters Ω2=9.3155×10^-20 cm^2, Ω4=8.4103×10^-20 cm^2, Ω6=1.5908×10^-20 cm^2, the fluorescence lifetime is calculated to be 2.03 ms for ^3F4 → ^3H6 transition, and the integrated emission cross section is 5.81×10^-18 cm^2. Room-temperature laser action near 2μm under diode pumping is experimentally evaluated in Tm：LSO. An optical-optical conversion efficiency of 9.1% and a slope efficiency of 16.2% are obtained with continuouswave maximum output power of 0.67 W. The emission wavelengths of Tm：LSO laser are centred around 2.06μm with spectral bandwidth of -13.6 nm.
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Project Supported by the Jilin Province Science and Technology Development Projects (20090348 and 20080511)
文摘Sr3SiO5:Eu2+ yellow phosphors for white LEDs were synthesized by high temperature solid state reaction method under a reductive atmosphere. The crystalline phases were examined with X-ray diffraction (XRD). Luminescence properties were studied, and effects of various fluxing agents BaCl2, MgF2, CaF2 and BaF2 on the emission spectra were also studied. The optimal Eu2+ concentration and flux were determined. Sr3SiO5: Eu2+ was obtained by firing the sample on optimal composition and fabrication process. The sa...
基金supported by National Natural Science Foundation of China(11475241)Science and Technology Commission of Shanghai Municipality(15DZ2251200)
文摘A systematical exploration of energy transfer processes in Lu2（1-x）Y2xSiO5：Ce（LYSO） crystals under vacuum ultraviolet-ultraviolet（VUV-UV） excitation was implemented. The relationship between energy transfer and scintillation properties was established. It is revealed that there are mainly three energy transfer types in the crystal i.e. host → Ce1/Ce2/STEs, Ce1 →Ce2 and STEs → Ce1/Ce2. The influence of Y content of the LYSO crystals on the energy transfer efficiency of the above processes was carefully analyzed. Besides, we find a special component of the crystal i.e. Y content = 45 at% at which the energy resolution and light output of the crystal perform the worst.
基金supported by the Research Foundation for Youth Scholars of Beijing Technology and Business University (QNJJ2019-06,PXM2019_014213_000007)
文摘A novel single-phase Sm^3+activated Ca5(PO4)2SiO4 phosphor was successfully fabricated via a conventional solid-state method,which can be e fficie ntly excited by near ultraviolet(n-UV)light-emitting chips.The crystal structure and luminescence properties were characterized and analyzed systematically by using relevant instruments.The Ca5(PO4)2SiO4:Sm^3+phosphor shows an orange-red emission peaking at600 nm under the excitation of 403 nm and the optimal doping concentration of Sm^3+is determined to be 0.08,The critical distance of Ca5(PO4)2SiO4:0.08 Sm^3+is calculated to be 1.849 nm and concentration quenching mechanism of the Sm^3+in Ca5(PO4)2SiO4 host is ascribed to energy transfer between nearestneighbor activators.The decay time of Ca5(PO4)2 SiO4:0,08 Sm^3+is determined to be 1.1957 ms.In addition,the effect of temperature on the emission intensity was also studied,72.4%of the initial intensity is still preserved at 250℃,better thermal stability compared to commercial phosphor YAG:Ce^3+indicates that Ca5(PO4)2SiO4:0.08 Sm^3+has excellent thermal stability and active energy is deduced to be 0.130 eV.All the results demonstrate that orange-red emitting Ca5(PO4)2SiO4:0.08 Sm3+phosphor exhibits good luminescent properties.Owing to the excellent thermal quenching luminescence property,Ca5(PO4)2SiO4:0.08 Sm^3+phosphor can be applied in n-UV white light emitting diodes and serve as the warm part of white light.
文摘Undoped LaAlO3 and 1 at.%Ce:LaAlO3 single crystals were grown by the Czochralski process.Absorption and fluorescence spectra were measured at room temperature.Detailed energy levels structure of Ce:LaAlO3 was determined.In this paper,two viewpoints were provided.The first one is:the energy levels structure of Ce:LaAlO3 is very similar to that of Ce:Lu2(SiO4)O which is a well-known scintillator.In the energy levels structure of Ce:LaAlO3 and Ce:Lu2(SiO4)O,the lowest 5d energy level of Ce 3+ is located below the bottom of the conduction band of host crystal and the other higher 5d energy levels of Ce 3+ are located above the bottom of the conduction band of host crystal.The second one is:Ce:LaAlO3 single crystal may not be suitable for scintillation application;by comparing the energy levels structures of Ce:LaAlO3 and Ce:Lu2(SiO4)O,the large energy difference(1.13 eV)between the two lowest 5d energy levels of Ce 3+ in LaAlO3 is a crucial factor that causes the luminescence quenching.
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.
