A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fabricated via low-cost ecofriendly green combustion technique using Aloe vera gel as fuel.The phase purity of the samples were confirm...A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fabricated via low-cost ecofriendly green combustion technique using Aloe vera gel as fuel.The phase purity of the samples were confirmed by the powder X-ray diffraction(PXRD)technique.Pure single-phase tetragonal structure is observed from the PXRD results with no additional impurity peaks.The band gap energy of the fabricated powders was estimated by diffuse reflectance spectra(DRS)and is found to be in the range of 4.01-5.98 eV.A high resolution scanning electron microscope(SEM)was used to study the morphological behaviour of the samples.Honeycomb-like structures are observed from the SEM results.The particle size was evaluated by transmission electron microscopy(TEM)and is found to be~50 nm.The interplanar distance is found to be 0.53 nm.Photoluminescence properties were systematically studied in detail.The phosphors are successfully excited at 403 nm NUV light,producing reddish-orange characteristic emission.The emission peaks are centered at 558(^(4)G_(5/2)→^(6)H_(5/2)),607(^(4)G_(5/2)→^(6)H_(7/2))and 645 nm(^(4)G_(5/2)→^(6)H_(9/2)),respectively.Among the observed peaks the red emanation(^(4)G_(5/2)→^(6)H_(7/2))is stronger than the orange emission(^(4)G_(5/2)→^(6)H_(5/2))in the current investigation.The photoluminescent concentration quenching is noticed above 5 mol%Sm^(3+)ion doping content.The dipole-dipole interaction resulting in cross relaxation is found to be the principal cause of concentration quenching mechanism.The color features such as Commission Internationale de I’Eclairage(CIE)and correlated color temperature(CCT)were studied in detail.The optimized chromaticity coordinates were estimated to be(0.6363,0.3632),which fall in the reddish-orange region.The average CCT value obtained is 3362 K.The average color purity is found to be~82%.Sm^(3+)incorporated Ca_(2)MgSi_(2)O_(7) samples are possible contender for single white light generation commercial candidates owing to their strong hypersensitivity of Sm展开更多
We synthesized reddish-orange luminescent La_(10)W_(22)O_(81)(LWO):Sm^(3+)microphosphors by hydrothermalassisted solid-state reaction.X-ray diffraction analysis reveals that all the studied phosphors crystallize in an...We synthesized reddish-orange luminescent La_(10)W_(22)O_(81)(LWO):Sm^(3+)microphosphors by hydrothermalassisted solid-state reaction.X-ray diffraction analysis reveals that all the studied phosphors crystallize in an orthorhombic structure in the Pbcn space group(60),Field emission scanning electron microscopy indicates that the LWO:1.5 mol% Sm^(3+)phosphor displays a smooth-surfaced hexagonal rod-like shape,with a closed shape at both ends,and high-resolution transmission electron microscopy demonstrates a robust crystalline structure.The chemical composition and valence states of the phosphor were investigated using X-ray photoelectron spectroscopy.At 403 nm excitation,LWO:1.5 mol% Sm3+exhibits maximum intensity with the strongest band at 596 nm(^(4)G_(5/2)→^(6)H_(7/2)) in the reddish-orange region.The intensity of Sm^(3+) emission decreases beyond 1.5 mol% owing to concentration quenching regulated by dipole-quadrupole interaction between Sm^(3+)ions.The optimized microphosphor LWO:1.5 mol% Sm^(3+)exhibits color coordinates(0.5760,0.4207),which is close to that of the Amber LED-NSPAR 70 BS(0.570,0.420),displaying the highest color purity of 99.2% and correlated color temperature of 1694 K.In addition,both breast cancer cells MCF-7 and normal lung fibroblasts WI-38 were tested for toxicity with the optimized microphosphor.It is found that the LWO:1.5 Sm^(3+)microphosphor is extremely toxic to cancer cells,but not to normal cells.Based on these results,LWO:Sm^(3+)microphosphor can serve as a biomedical candidate for the treatment of cancer,as well as a potential multicolor emitting material for w-LEDs.展开更多
In this work,through a facile method of low-temperature(only 350℃)self-reduction,1D nano-sized M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)blue phosphors with highly efficient performance can be obtained.The crystal structure,...In this work,through a facile method of low-temperature(only 350℃)self-reduction,1D nano-sized M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)blue phosphors with highly efficient performance can be obtained.The crystal structure,morphology and photoluminescence(PL)properties including thermal stability of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors were investigated.The M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors show broad band excitation spectra and narrow band emission spectra.The photoluminescence quantum yields(PLQY)of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)are as high as 98%and 87.2%,respectively.Furthermore,the color purities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)can reach 99.1%and 93.2%,respectively,When heated up to 150℃,the emission intensities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors can still keep 72.7%and80.0%,respectively.Finally,the above-mentioned phosphors exhibit outstanding performance when manufacturing WLEDs.展开更多
This study presents the photoluminescence characteristic analysis of a series of red phosphors of KAlSiO_(4):1.5 mol%Sm^(3+),x mol%Eu^(3+)(x=2,3,4,5,6,7)prepared via high-temperature solid-phase reaction.The results s...This study presents the photoluminescence characteristic analysis of a series of red phosphors of KAlSiO_(4):1.5 mol%Sm^(3+),x mol%Eu^(3+)(x=2,3,4,5,6,7)prepared via high-temperature solid-phase reaction.The results show that the X-ray diffraction(XRD)refinement results are reliable.The unit cell parameters and volume gradually decrease as the Eu^(3+) concentration increases,resulting in a grain size reduction of 10.22%.When x=6,the emission peaks of Sm^(3+) at 564,601,and 651 nm disappear completely,and the corresponding full width at half maximum becomes 0.At 610 nm,the emission peak intensity of Eu^(3+) is increased by a factor of 4.8.The resonant non-radiative energy transfer effect is greater than the co-excitation effect.A maximum energy transfer efficiency of 97.8%is achieved.The integral area at 610 nm is as high as 85%.The color purity of the phosphor is as high as 92.97%,and the internal quantum yield gradually changes from 32%to 51%.Ultimately,these results confirm that the silicate phosphor is suitable for the red component in the three primary color phosphors of white light-emitting diodes.展开更多
The encapsulation of a rare earth (RE) complex Eu(DBM)(3)phen in modified S1-MCM-41 with 3-aminopropyltriethoxysilane is reported for the first time. The luminescence intensity of the RE complex in the modified Si-MCM...The encapsulation of a rare earth (RE) complex Eu(DBM)(3)phen in modified S1-MCM-41 with 3-aminopropyltriethoxysilane is reported for the first time. The luminescence intensity of the RE complex in the modified Si-MCM-41 is about 9 times as strong as in unmodified Si-MCM-41 and the luminescence of the RE complex in the modified SI-MCM-41 has good color purity.展开更多
文摘A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fabricated via low-cost ecofriendly green combustion technique using Aloe vera gel as fuel.The phase purity of the samples were confirmed by the powder X-ray diffraction(PXRD)technique.Pure single-phase tetragonal structure is observed from the PXRD results with no additional impurity peaks.The band gap energy of the fabricated powders was estimated by diffuse reflectance spectra(DRS)and is found to be in the range of 4.01-5.98 eV.A high resolution scanning electron microscope(SEM)was used to study the morphological behaviour of the samples.Honeycomb-like structures are observed from the SEM results.The particle size was evaluated by transmission electron microscopy(TEM)and is found to be~50 nm.The interplanar distance is found to be 0.53 nm.Photoluminescence properties were systematically studied in detail.The phosphors are successfully excited at 403 nm NUV light,producing reddish-orange characteristic emission.The emission peaks are centered at 558(^(4)G_(5/2)→^(6)H_(5/2)),607(^(4)G_(5/2)→^(6)H_(7/2))and 645 nm(^(4)G_(5/2)→^(6)H_(9/2)),respectively.Among the observed peaks the red emanation(^(4)G_(5/2)→^(6)H_(7/2))is stronger than the orange emission(^(4)G_(5/2)→^(6)H_(5/2))in the current investigation.The photoluminescent concentration quenching is noticed above 5 mol%Sm^(3+)ion doping content.The dipole-dipole interaction resulting in cross relaxation is found to be the principal cause of concentration quenching mechanism.The color features such as Commission Internationale de I’Eclairage(CIE)and correlated color temperature(CCT)were studied in detail.The optimized chromaticity coordinates were estimated to be(0.6363,0.3632),which fall in the reddish-orange region.The average CCT value obtained is 3362 K.The average color purity is found to be~82%.Sm^(3+)incorporated Ca_(2)MgSi_(2)O_(7) samples are possible contender for single white light generation commercial candidates owing to their strong hypersensitivity of Sm
基金Project supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1A6A1A03039493) by the Ministry of Science,Information and Communications Technology (ICT) and Future Planning (2022R1A2C1009389)。
文摘We synthesized reddish-orange luminescent La_(10)W_(22)O_(81)(LWO):Sm^(3+)microphosphors by hydrothermalassisted solid-state reaction.X-ray diffraction analysis reveals that all the studied phosphors crystallize in an orthorhombic structure in the Pbcn space group(60),Field emission scanning electron microscopy indicates that the LWO:1.5 mol% Sm^(3+)phosphor displays a smooth-surfaced hexagonal rod-like shape,with a closed shape at both ends,and high-resolution transmission electron microscopy demonstrates a robust crystalline structure.The chemical composition and valence states of the phosphor were investigated using X-ray photoelectron spectroscopy.At 403 nm excitation,LWO:1.5 mol% Sm3+exhibits maximum intensity with the strongest band at 596 nm(^(4)G_(5/2)→^(6)H_(7/2)) in the reddish-orange region.The intensity of Sm^(3+) emission decreases beyond 1.5 mol% owing to concentration quenching regulated by dipole-quadrupole interaction between Sm^(3+)ions.The optimized microphosphor LWO:1.5 mol% Sm^(3+)exhibits color coordinates(0.5760,0.4207),which is close to that of the Amber LED-NSPAR 70 BS(0.570,0.420),displaying the highest color purity of 99.2% and correlated color temperature of 1694 K.In addition,both breast cancer cells MCF-7 and normal lung fibroblasts WI-38 were tested for toxicity with the optimized microphosphor.It is found that the LWO:1.5 Sm^(3+)microphosphor is extremely toxic to cancer cells,but not to normal cells.Based on these results,LWO:Sm^(3+)microphosphor can serve as a biomedical candidate for the treatment of cancer,as well as a potential multicolor emitting material for w-LEDs.
基金Project supported by the National Natural Science Foundation of China(22003035,22073061)the Natural Science Foundation of Shaanxi Province Department of Education(21JK0587)+2 种基金the Natural Science Foundation of Shaanxi Province(2020GY-237)the Foundation of Shaanxi Xueqian Normal University(2020YBKJ70)Innovation and Entrepreneurship Training Program for College Students in Shaanxi Province(S202014390037)。
文摘In this work,through a facile method of low-temperature(only 350℃)self-reduction,1D nano-sized M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)blue phosphors with highly efficient performance can be obtained.The crystal structure,morphology and photoluminescence(PL)properties including thermal stability of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors were investigated.The M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors show broad band excitation spectra and narrow band emission spectra.The photoluminescence quantum yields(PLQY)of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)are as high as 98%and 87.2%,respectively.Furthermore,the color purities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)can reach 99.1%and 93.2%,respectively,When heated up to 150℃,the emission intensities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors can still keep 72.7%and80.0%,respectively.Finally,the above-mentioned phosphors exhibit outstanding performance when manufacturing WLEDs.
基金Project supported by the Scientific Research Projects of Universities in Xinjiang Autonomous Region(XJEDU2017I009)the Scientific Research and Innovation Project of Postgraduates in Xinjiang Autonomous Region(XJ2020G233)。
文摘This study presents the photoluminescence characteristic analysis of a series of red phosphors of KAlSiO_(4):1.5 mol%Sm^(3+),x mol%Eu^(3+)(x=2,3,4,5,6,7)prepared via high-temperature solid-phase reaction.The results show that the X-ray diffraction(XRD)refinement results are reliable.The unit cell parameters and volume gradually decrease as the Eu^(3+) concentration increases,resulting in a grain size reduction of 10.22%.When x=6,the emission peaks of Sm^(3+) at 564,601,and 651 nm disappear completely,and the corresponding full width at half maximum becomes 0.At 610 nm,the emission peak intensity of Eu^(3+) is increased by a factor of 4.8.The resonant non-radiative energy transfer effect is greater than the co-excitation effect.A maximum energy transfer efficiency of 97.8%is achieved.The integral area at 610 nm is as high as 85%.The color purity of the phosphor is as high as 92.97%,and the internal quantum yield gradually changes from 32%to 51%.Ultimately,these results confirm that the silicate phosphor is suitable for the red component in the three primary color phosphors of white light-emitting diodes.
基金We are grateful to the National Natural Science Foundation of ChinaNational Key Project for Fundamental Research, the Natio
文摘The encapsulation of a rare earth (RE) complex Eu(DBM)(3)phen in modified S1-MCM-41 with 3-aminopropyltriethoxysilane is reported for the first time. The luminescence intensity of the RE complex in the modified Si-MCM-41 is about 9 times as strong as in unmodified Si-MCM-41 and the luminescence of the RE complex in the modified SI-MCM-41 has good color purity.
