Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting source.Phosphors based on the transmissive configuration model could not simultaneously meet the requir...Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting source.Phosphors based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal stability.In this study,a novel composite structure ceramic was designed,including Al_(2)O_(3)-YAG:Ce/YAG layered ceramic with a size of 1 mm×1 mm for lighting,and Al_(2)O_(3) ceramic(φ=16.0 mm)was used as the wrapping material due to its outstanding thermal stability.The prepared ceramics exhibited excellent thermal performance and no yellow ring phenomenon.Through this design,we achieved the match of the intensity distribution of the blue and yellow lights,resulting in a high angular color uniformity of 0.9 with a view angle of±80°.All ceramics showed no luminous saturation phenomenon,even the laser power density was increased up to 47.51 W/mm^(2).A high-brightness white-light source with a luminous flux of 618 lm,a luminous efficiency of 126 lm/W,a CCT of 6615 K,and a CRI of 69.9 was obtained in the transmissive configuration.In particular,the surface temperature of the ceramic was as low as 74.1℃ under a high laser radiation(47.51 W/mm^(2)).These results indicate that Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.展开更多
A series of K3Gd1-x-y（PO4）2：xCe^3＋, yTb^3＋ phosphors are synthesized by the solid-sate reaction method. X-ray diffraction and photoluminescence spectra are utilized to characterize the structures and luminescence...A series of K3Gd1-x-y（PO4）2：xCe^3＋, yTb^3＋ phosphors are synthesized by the solid-sate reaction method. X-ray diffraction and photoluminescence spectra are utilized to characterize the structures and luminescence properties of the as-synthesized phosphors. Co-doping of Ce^3＋ enhances the emission intensity of Tb^3＋ greatly through an efficient energy transfer process from Ce^3＋ to Tb^3＋. The energy transfer is confirmed by photoluminescence spectra and decay time curves analysis. The efficiency and mechanism of energy transfer are investigated carefully. Moreover, due to the non- concentration quenching property of K3Tb（PO4）2, the photoluminescence spectra of K3Tb1-x（PO4）2：xCe^3＋ are studied and the results show that when x = 0.11 the strongest Tb^3＋ green emission can be realized.展开更多
Ultrafine-grained Al_(2)O_(3)–rare earth:yttrium aluminium garnet(Al_(2)O_(3)–RE:YAG)(RE=Ce;Ce+Gd)composite ceramics were obtained for the first time by reactive spark plasma sintering(SPS)using commercially availab...Ultrafine-grained Al_(2)O_(3)–rare earth:yttrium aluminium garnet(Al_(2)O_(3)–RE:YAG)(RE=Ce;Ce+Gd)composite ceramics were obtained for the first time by reactive spark plasma sintering(SPS)using commercially available initial oxide powders.The effect of key sintering parameters(temperature,dwell time,and external pressure(P_(load)))on densification peculiarities,structural-phase states,and luminescent properties of composites was studied comprehensively.Differences in phase formation and densification between Ce-doped and Ce,Gd-codoped systems were shown.Parameters of reactive SPS,at which there is partial melting with the formation of near-eutectic zones of the Al_(2)O_(3)–YAG system/coexistence of several variations of the YAG-type phase,were established.Pure corundum–garnet biphasic ceramics with an optimal balance between microstructural and luminescence performance were synthesized at 1425℃/30 min/30–60 MPa.The external quantum efficiency(EQE)of the phosphor converters reached 80.7%and 72%with close lifetime of~63.8 ns,similar to those of commercial Ce:YAG materials,which is promising for further applications in the field of high-power white light-emitting diodes(WLEDs)and laser diodes(LDs).展开更多
Abstract： Monophasic Ce3＋ and Pr3＋ co-doped yttrium aluminum garnet （YAG：Ce3＋,pr3＋） nanoparticles with good dispersity and uniform grain sizes in the range of 50-80 nm were prepared by a two-step route, which ...Abstract： Monophasic Ce3＋ and Pr3＋ co-doped yttrium aluminum garnet （YAG：Ce3＋,pr3＋） nanoparticles with good dispersity and uniform grain sizes in the range of 50-80 nm were prepared by a two-step route, which consisted of a modified co-precipitation preparation of mixed metal hydroxide hydrate intermediates at low temperature of about 40℃ and a subsequent calcination conversion of the synthesized intermediates to crystalline nanoparticle products at about 1000℃. The influences of both the lanthanide ion （Ce3＋ and Pr3＋） doping concentration and different doping （Ce3＋/pr3＋） ratio on the photoluminescence intensity were systematically investigated. The synthesized （Ce0.6Pr0.4）0.04Y2.96Al5O12 nanoparticles were near spherical nanoclusters with good dispersity and uniform sizes in the range of 50-80 nm for about 85% of the particles. The strongest photoluminescence intensity was observed for the （Ce0.6Pr0.4）0.04Y2.96Al5O12 nanoparticle products.展开更多
In this research, cerium （III） nitrate hexahydrate （Ce（NO3）3·6H2O） and ammonium molybdate tetrahydrate （（NH4）6Mo7O24·4H2O） with Ce3＋-to-Mo6＋ molar ratio of 2：3 were dissolved in 40 ml different ...In this research, cerium （III） nitrate hexahydrate （Ce（NO3）3·6H2O） and ammonium molybdate tetrahydrate （（NH4）6Mo7O24·4H2O） with Ce3＋-to-Mo6＋ molar ratio of 2：3 were dissolved in 40 ml different solvents of deionized （DI） water, polyethylene glycol （PEG） and ethylene glycol （EG） to form different solutions which were followed by adjusting pH from the traditional values to 7.0 and 10.0 with 1 mol.L-1 sodium hydroxide （NaOH）. Subsequently, the solutions were processed by 270-W microwave-hydrother- mal/solvothermal method. Phase, morphology, vibrational modes and photonic properties were fully characterized by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR）, Raman spectrophotometry, ultraviolet-visible （UV-Vis） absorption and photoluminescence （PL） spectroscopy. The as-synthe-sized products were pure cerium molybdenum oxide （Ce2（MoO4）3） of nanoparticles clustered together as nano- plates in DI water and PEG solvents, and of spindle-like nanoparticles in EG solvent, including the presence of Ce-O-H mode and MoO4 units. The results show that direct energy gaps of the first two have the same value of 2.30 eV, and that of the last is 2.80 eV, including their blue emission at the same wavelength of 488 nm.展开更多
Sr2MgSi2OT：Tb3＋,Ce3＋ phosphors were synthesized by solid-state reaction and placed in a muffle furnace in a reducing at- mosphere at 1300 ~C for 3 h. Photoluminescence properties and energy transfer were investigat...Sr2MgSi2OT：Tb3＋,Ce3＋ phosphors were synthesized by solid-state reaction and placed in a muffle furnace in a reducing at- mosphere at 1300 ~C for 3 h. Photoluminescence properties and energy transfer were investigated. The Ce3＋/Tb3＋ energy transfer was thoroughly investigated by their emission/excitation spectra and photoluminescence lifetime, there was shortened lifetime of Ce3＋ （from 51.31 to 50.06 ns） which could support evidence of energy transfer from Ce3＋ to Tb3＋ in the host. The varied emitted color of Srj.97_yMgSi2OT：0.03Tb3＋,yCe3＋phosphors could be achieved by altering the concentration of Ce3＋, the chromaticity coordinates （x, y） varied from （0.225, 0.376） to （0.172, 0.231）. In Srl.96MgSi207：0.03Tb3＋,0.01 Ce3＋ phosphors, the results indicated that Sr2MgSi207：Tb3＋,Ce3＋ might be useful as tunable phosphors for ultraviolet white-light-emitting diodes.展开更多
基金the National Key R&D Program of China(2021YFB3501700,2023YFB3506600)National Natural Science Foundation of China(52202135,61975070,and 52302141)+5 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),International S&T Cooperation Program of Jiangsu Province(BZ2023007)Key Research and Development Project of Jiangsu Province(BE2023050,BE2021040)Natural Science foundation of Jiangsu Province(BK20221226)Graduate Research and Innovation Projects of Jiangsu Province(KYCX22_2845)Special Project for Technology Innovation of Xuzhou City(KC23380,KC21379,KC22461,and KC22497)Open Project of State Key Laboratory of Crystal Materials(KF2205).
文摘Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting source.Phosphors based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal stability.In this study,a novel composite structure ceramic was designed,including Al_(2)O_(3)-YAG:Ce/YAG layered ceramic with a size of 1 mm×1 mm for lighting,and Al_(2)O_(3) ceramic(φ=16.0 mm)was used as the wrapping material due to its outstanding thermal stability.The prepared ceramics exhibited excellent thermal performance and no yellow ring phenomenon.Through this design,we achieved the match of the intensity distribution of the blue and yellow lights,resulting in a high angular color uniformity of 0.9 with a view angle of±80°.All ceramics showed no luminous saturation phenomenon,even the laser power density was increased up to 47.51 W/mm^(2).A high-brightness white-light source with a luminous flux of 618 lm,a luminous efficiency of 126 lm/W,a CCT of 6615 K,and a CRI of 69.9 was obtained in the transmissive configuration.In particular,the surface temperature of the ceramic was as low as 74.1℃ under a high laser radiation(47.51 W/mm^(2)).These results indicate that Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11204113,61265004,and 51272097)the Foundation of Application Research of Yunnan Province,China (Grant No.2011FB022)+2 种基金the Chinese Specialized Research Fund for the Doctoral Program of Higher Education (Grant No.20115314120001)the Postdoctoral Science Foundation of China (Grant No.2011M501424)the National Basic Research Program of China (Grant No.2011CB211708)
文摘A series of K3Gd1-x-y（PO4）2：xCe^3＋, yTb^3＋ phosphors are synthesized by the solid-sate reaction method. X-ray diffraction and photoluminescence spectra are utilized to characterize the structures and luminescence properties of the as-synthesized phosphors. Co-doping of Ce^3＋ enhances the emission intensity of Tb^3＋ greatly through an efficient energy transfer process from Ce^3＋ to Tb^3＋. The energy transfer is confirmed by photoluminescence spectra and decay time curves analysis. The efficiency and mechanism of energy transfer are investigated carefully. Moreover, due to the non- concentration quenching property of K3Tb（PO4）2, the photoluminescence spectra of K3Tb1-x（PO4）2：xCe^3＋ are studied and the results show that when x = 0.11 the strongest Tb^3＋ green emission can be realized.
基金supported by the Russian Science Foundation(No.20-73-10242)Also,this work was partially supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA22010301)+3 种基金the International Partnership Program of Chinese Academy of Sciences(No.121631KYSB20200039)the International Cooperation Project of Shanghai Science and Technology Commission(No.20520750200)Denis Yu.Kosyanov is grateful to the Council on grants of the President of the Russian Federation(No.SP-3221.2022.1)for supporting the studies devoted to obtaining advanced ceramic materialsThe SR XRD measurements were done at the shared research center SSTRC on the basis of the VEPP-4-VEPP-2000 complex at the Budker Institute of Nuclear Physics SB RAS.
文摘Ultrafine-grained Al_(2)O_(3)–rare earth:yttrium aluminium garnet(Al_(2)O_(3)–RE:YAG)(RE=Ce;Ce+Gd)composite ceramics were obtained for the first time by reactive spark plasma sintering(SPS)using commercially available initial oxide powders.The effect of key sintering parameters(temperature,dwell time,and external pressure(P_(load)))on densification peculiarities,structural-phase states,and luminescent properties of composites was studied comprehensively.Differences in phase formation and densification between Ce-doped and Ce,Gd-codoped systems were shown.Parameters of reactive SPS,at which there is partial melting with the formation of near-eutectic zones of the Al_(2)O_(3)–YAG system/coexistence of several variations of the YAG-type phase,were established.Pure corundum–garnet biphasic ceramics with an optimal balance between microstructural and luminescence performance were synthesized at 1425℃/30 min/30–60 MPa.The external quantum efficiency(EQE)of the phosphor converters reached 80.7%and 72%with close lifetime of~63.8 ns,similar to those of commercial Ce:YAG materials,which is promising for further applications in the field of high-power white light-emitting diodes(WLEDs)and laser diodes(LDs).
基金Project supported by the National High Technology Research and Development Program of China(863 Program)(2013AA031901)the National Natural Science Foundation of China(51425202)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20160093)Topnotch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)
文摘Abstract： Monophasic Ce3＋ and Pr3＋ co-doped yttrium aluminum garnet （YAG：Ce3＋,pr3＋） nanoparticles with good dispersity and uniform grain sizes in the range of 50-80 nm were prepared by a two-step route, which consisted of a modified co-precipitation preparation of mixed metal hydroxide hydrate intermediates at low temperature of about 40℃ and a subsequent calcination conversion of the synthesized intermediates to crystalline nanoparticle products at about 1000℃. The influences of both the lanthanide ion （Ce3＋ and Pr3＋） doping concentration and different doping （Ce3＋/pr3＋） ratio on the photoluminescence intensity were systematically investigated. The synthesized （Ce0.6Pr0.4）0.04Y2.96Al5O12 nanoparticles were near spherical nanoclusters with good dispersity and uniform sizes in the range of 50-80 nm for about 85% of the particles. The strongest photoluminescence intensity was observed for the （Ce0.6Pr0.4）0.04Y2.96Al5O12 nanoparticle products.
基金financially supported by Thailand's Office of the Higher Education Commission through the National Research University Project for Chiang Mai University
文摘In this research, cerium （III） nitrate hexahydrate （Ce（NO3）3·6H2O） and ammonium molybdate tetrahydrate （（NH4）6Mo7O24·4H2O） with Ce3＋-to-Mo6＋ molar ratio of 2：3 were dissolved in 40 ml different solvents of deionized （DI） water, polyethylene glycol （PEG） and ethylene glycol （EG） to form different solutions which were followed by adjusting pH from the traditional values to 7.0 and 10.0 with 1 mol.L-1 sodium hydroxide （NaOH）. Subsequently, the solutions were processed by 270-W microwave-hydrother- mal/solvothermal method. Phase, morphology, vibrational modes and photonic properties were fully characterized by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR）, Raman spectrophotometry, ultraviolet-visible （UV-Vis） absorption and photoluminescence （PL） spectroscopy. The as-synthe-sized products were pure cerium molybdenum oxide （Ce2（MoO4）3） of nanoparticles clustered together as nano- plates in DI water and PEG solvents, and of spindle-like nanoparticles in EG solvent, including the presence of Ce-O-H mode and MoO4 units. The results show that direct energy gaps of the first two have the same value of 2.30 eV, and that of the last is 2.80 eV, including their blue emission at the same wavelength of 488 nm.
基金Project supported by Mineral and Ore Resources Comprehensive Utilization of Advanced Technology Popularization and Practical Research(MORCUATPPR)funded by China Geological Survey(12120113088300)
文摘Sr2MgSi2OT：Tb3＋,Ce3＋ phosphors were synthesized by solid-state reaction and placed in a muffle furnace in a reducing at- mosphere at 1300 ~C for 3 h. Photoluminescence properties and energy transfer were investigated. The Ce3＋/Tb3＋ energy transfer was thoroughly investigated by their emission/excitation spectra and photoluminescence lifetime, there was shortened lifetime of Ce3＋ （from 51.31 to 50.06 ns） which could support evidence of energy transfer from Ce3＋ to Tb3＋ in the host. The varied emitted color of Srj.97_yMgSi2OT：0.03Tb3＋,yCe3＋phosphors could be achieved by altering the concentration of Ce3＋, the chromaticity coordinates （x, y） varied from （0.225, 0.376） to （0.172, 0.231）. In Srl.96MgSi207：0.03Tb3＋,0.01 Ce3＋ phosphors, the results indicated that Sr2MgSi207：Tb3＋,Ce3＋ might be useful as tunable phosphors for ultraviolet white-light-emitting diodes.
