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 red upconversion emission of Ho^(3+)ions,in the optical window of biological tissue,exhibits excellent prospects in biological applications.This study aims to enhance the red upconversion emission intensity of Ho^...The red upconversion emission of Ho^(3+)ions,in the optical window of biological tissue,exhibits excellent prospects in biological applications.This study aims to enhance the red upconversion emission intensity of Ho^(3+)ions in NaLuF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+) nanoparticles through building different core–shell structures with different excitation wavelengths.A significantly enhanced red upconversion emission with a higher red-to-green ratio was successfully obtained in NaLuF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaLuF_(4) core–shell nanoparticles by introducing the Yb^(3+)and Yb^(3+)/Nd^(3+)ions into the NaLuF_(4) shell,with enhancement of the red emission occurring when Yb^(3+)and Nd^(3+)ions in the shell transfer more excitation energy to the Ho^(3+)ions.Investigation of the red emission enhancement mechanism is based on spectral characteristics and lifetimes.We examined the synergistic effect of dual-wavelength co-excitation NaLuF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaLuF_(4):10%Yb^(3+)/15%Nd^(3+)core–shell nanoparticles to establish optimal excitation conditions.It is hoped that this method,using red upconversion emission core–shell nanoparticles with multi-mode excitation,can provide new ways to expand the applications of rare-earth luminescent materials in biomedicine and anti-counterfeiting.展开更多
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Project supported by the National Natural Science Foundation of China(12004303,62005213)the Natural Science Basic Research Plan in Shaanxi Province of China(2019JQ-864)+2 种基金the Key R&D Program of Shaanxi Province(2020GY-101,2020GY-127)the Xi’an Science and Technology Innovation Talent Service Enterprise Project(2020KJRC0107,2020KJRC0112)Xi’an University of Posts and Telecommunications Joint Postgraduate Cultivation Workstation(YJGJ201905)。
文摘The red upconversion emission of Ho^(3+)ions,in the optical window of biological tissue,exhibits excellent prospects in biological applications.This study aims to enhance the red upconversion emission intensity of Ho^(3+)ions in NaLuF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+) nanoparticles through building different core–shell structures with different excitation wavelengths.A significantly enhanced red upconversion emission with a higher red-to-green ratio was successfully obtained in NaLuF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaLuF_(4) core–shell nanoparticles by introducing the Yb^(3+)and Yb^(3+)/Nd^(3+)ions into the NaLuF_(4) shell,with enhancement of the red emission occurring when Yb^(3+)and Nd^(3+)ions in the shell transfer more excitation energy to the Ho^(3+)ions.Investigation of the red emission enhancement mechanism is based on spectral characteristics and lifetimes.We examined the synergistic effect of dual-wavelength co-excitation NaLuF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaLuF_(4):10%Yb^(3+)/15%Nd^(3+)core–shell nanoparticles to establish optimal excitation conditions.It is hoped that this method,using red upconversion emission core–shell nanoparticles with multi-mode excitation,can provide new ways to expand the applications of rare-earth luminescent materials in biomedicine and anti-counterfeiting.
