A novel orange-red emitting Ba3 Y4 O9：Sm^（3＋） phosphors were prepared by a high temperature solidstate reaction in air. X-ray diffraction（XRD）, photoluminescence spectra, fluorescence decay and temperature-depen...A novel orange-red emitting Ba3 Y4 O9：Sm^（3＋） phosphors were prepared by a high temperature solidstate reaction in air. X-ray diffraction（XRD）, photoluminescence spectra, fluorescence decay and temperature-dependent emission spectra were utilized to characterize the structure and luminescence properties. The results show that the excitation spectrum includes a series of linear peaks at350, 367, 382, 410, 424, 445, 470 and 495 nm, respectively. Under 410 nm excitation, the emission peaks were located at 574 nm（~4 G（5/2）-~6 H（5/2））, 608 nm（~4 G（5/2）-~6 H（7/2））,659 nm（~4 G（5/2）-~6 H（9/2）） and722 nm（~4 G（5/2）-~6 H（11/2））, respectively. The concentration quenching occurs when x equals 0.08 for Ba3 Y（4-x）O9：xSm^（3＋） phosphor and its mechanism is ascribed to the dipole-dipole interaction. The chromaticity coordinates of Ba3 Y（3.92）O9：0.08 Sm^（3＋） phosphor are in the orange-red region. The temperature-dependent study shows that this phosphor has excellent luminescence thermal-stability.And the luminescence intensity of Ba3 Y（3.92）O9：0.08 Sm^（3＋） phosphor at 473 K only declines by about25.75% of its initial intensity. The experimental data indicate that Ba3 Y4 O9：Sm^（3＋） phosphor may be promising as an orange-red emitting phosphor for white light emitting diodes.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
Lead halide perovskites,with high photoluminescence efficiency and narrow・band emission,are promising materials for display and lighting.However,the lead toxicity and environmental sensitivity hinder their potential a...Lead halide perovskites,with high photoluminescence efficiency and narrow・band emission,are promising materials for display and lighting.However,the lead toxicity and environmental sensitivity hinder their potential applications.Herein,a new antimony・doped lead-free inorganic perovskites variant Cs2SnCl6:xSb is designed and synthesized.The perovskite variant Cs2SnCl6:xSb exhibits a broadband orange-red emission,with a photoluminescence quantum yield(PLQY)of 37%.The photoluminescence of Cs2SnCl6:xSb is caused by the ionoluminescence of Sb3+within Cs2SnCl6 matrix,which is verified by temperature dependent photoluminescence(PL)and PL decay measurements.In addition,the all inorganic structure renders Cs2SnCl6:xSb with excellent thermal and water stability.Finally,a white light-emitting diode(white-LED)is fabricated by assembling Cs2SnCl6:0.59%Sb,Cs2SnCl6:2.75%Bi and Ba2Sr2SiO4:Eu2+onto the commercial UV LED chips,and the color rendering index(CRI)reaches 81.展开更多
Optogenetics,a technique that employs light for neuromodulation,has revolutionized the study of neural mechanisms and the treatment of neurological disorders due to its high spatiotemporal resolution and cell-type spe...Optogenetics,a technique that employs light for neuromodulation,has revolutionized the study of neural mechanisms and the treatment of neurological disorders due to its high spatiotemporal resolution and cell-type specificity.However,visible light,particularly blue and green light,commonly used in conventional optogenetics,has limited penetration in biological tissue.This limitation necessitates the implantation of optical fibers for light delivery,especially in deep brain regions,leading to tissue damage and experimental constraints.To overcome these challenges,the use of orange-red and infrared light with greater tissue penetration has emerged as a promising approach for tetherless optical neuromodulation.In this review,we provide an overview of the development and applications of tetherless optical neuromodulation methods with long wavelengths.We first discuss the exploration of orange-red wavelength-responsive rhodopsins and their performance in tetherless optical neuromodulation.Then,we summarize two novel tetherless neuromodulation methods using near-infrared light:upconversion nanoparticle-mediated optogenetics and photothermal neuromodulation.In addition,we discuss recent advances in mid-infrared optical neuromodulation.展开更多
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
Herein,double-perovskite Ba_(2)LaTaO_(6) Eu-doped orange-red phosphors were successfully synthesized using a high-temperature solid-phase method.The phosphor phase purity was investigated using X-ray diffraction and m...Herein,double-perovskite Ba_(2)LaTaO_(6) Eu-doped orange-red phosphors were successfully synthesized using a high-temperature solid-phase method.The phosphor phase purity was investigated using X-ray diffraction and microscopic morphology analyses.Their luminescence properties were investigated using absorption,emission,excitation,and temperature-dependent spectra.The transition mechanism mainly involves a magnetic-dipole transition with an energy transfer mode featuring multipole-multipole interactions,and concentration quenching is achieved via dipole-dipole interactions.In addition,the intensity of the temperature-dependent spectrum increases abnormally between 298 and 373 K,with the luminous intensity at 373 K increasing to 110%of that observed at room temperature.This phenomenon can be attributed to lattice defects in Ba_(2)LaTaO_(6):Eu^(3+),and the phosphor luminous intensity at473 K remains at 80.62%of that at room temperature.In addition,white-light-emitting diode devices based on this novel Ba_(2)LaTaO_(6):0.35Eu^(3+)phosphor were fabricated to evaluate the potential applications of the as-prepared phosphor.展开更多
基金supported by the National Key Research and Development Program of China(2016YFB0701003)Key Program of the Frontier Science of the Chinese Academy of Sciences(YZDY-SSW-JSC018)+1 种基金National Natural Science Foundation of China(51402288)Natural Science Foundation of Liaoning Province(201602674)
文摘A novel orange-red emitting Ba3 Y4 O9：Sm^（3＋） phosphors were prepared by a high temperature solidstate reaction in air. X-ray diffraction（XRD）, photoluminescence spectra, fluorescence decay and temperature-dependent emission spectra were utilized to characterize the structure and luminescence properties. The results show that the excitation spectrum includes a series of linear peaks at350, 367, 382, 410, 424, 445, 470 and 495 nm, respectively. Under 410 nm excitation, the emission peaks were located at 574 nm（~4 G（5/2）-~6 H（5/2））, 608 nm（~4 G（5/2）-~6 H（7/2））,659 nm（~4 G（5/2）-~6 H（9/2）） and722 nm（~4 G（5/2）-~6 H（11/2））, respectively. The concentration quenching occurs when x equals 0.08 for Ba3 Y（4-x）O9：xSm^（3＋） phosphor and its mechanism is ascribed to the dipole-dipole interaction. The chromaticity coordinates of Ba3 Y（3.92）O9：0.08 Sm^（3＋） phosphor are in the orange-red region. The temperature-dependent study shows that this phosphor has excellent luminescence thermal-stability.And the luminescence intensity of Ba3 Y（3.92）O9：0.08 Sm^（3＋） phosphor at 473 K only declines by about25.75% of its initial intensity. The experimental data indicate that Ba3 Y4 O9：Sm^（3＋） phosphor may be promising as an orange-red emitting phosphor for white light emitting diodes.
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.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.5176114504&61725401 and 51702107)the National Key R&D Program of China(No.2016YFB0700702)+1 种基金the China Postdoctoral Science Foundation(No.2018M632843)The authors thank the Analytical and Testing Center of HU ST and the facility support of the Center for Nanoscale Characterization and Devices,WNLO.The work at Tokyo Institute of Technology was conducted under the Tokodai Institute for Element Strategy(TIES)funded by the MEXT Elements Strategy Initiative to Form Core Research Center.
文摘Lead halide perovskites,with high photoluminescence efficiency and narrow・band emission,are promising materials for display and lighting.However,the lead toxicity and environmental sensitivity hinder their potential applications.Herein,a new antimony・doped lead-free inorganic perovskites variant Cs2SnCl6:xSb is designed and synthesized.The perovskite variant Cs2SnCl6:xSb exhibits a broadband orange-red emission,with a photoluminescence quantum yield(PLQY)of 37%.The photoluminescence of Cs2SnCl6:xSb is caused by the ionoluminescence of Sb3+within Cs2SnCl6 matrix,which is verified by temperature dependent photoluminescence(PL)and PL decay measurements.In addition,the all inorganic structure renders Cs2SnCl6:xSb with excellent thermal and water stability.Finally,a white light-emitting diode(white-LED)is fabricated by assembling Cs2SnCl6:0.59%Sb,Cs2SnCl6:2.75%Bi and Ba2Sr2SiO4:Eu2+onto the commercial UV LED chips,and the color rendering index(CRI)reaches 81.
基金supported by China Postdoctoral Science Foundation(2022M723356),"From 0 to 1"Original Innovation Project of the Basic Frontier Scientific Research Program of the Chinese Academy of Sciences(29J20-015-Ⅲ)Chinese Academy of Sciences 100 Talents Project:Research on Task oriented Functional Brain Development of Infants(29J20-052-Ⅲ)Natural Science Basic Research Plan in Shaanxi Province of China(2022JQ544).
文摘Optogenetics,a technique that employs light for neuromodulation,has revolutionized the study of neural mechanisms and the treatment of neurological disorders due to its high spatiotemporal resolution and cell-type specificity.However,visible light,particularly blue and green light,commonly used in conventional optogenetics,has limited penetration in biological tissue.This limitation necessitates the implantation of optical fibers for light delivery,especially in deep brain regions,leading to tissue damage and experimental constraints.To overcome these challenges,the use of orange-red and infrared light with greater tissue penetration has emerged as a promising approach for tetherless optical neuromodulation.In this review,we provide an overview of the development and applications of tetherless optical neuromodulation methods with long wavelengths.We first discuss the exploration of orange-red wavelength-responsive rhodopsins and their performance in tetherless optical neuromodulation.Then,we summarize two novel tetherless neuromodulation methods using near-infrared light:upconversion nanoparticle-mediated optogenetics and photothermal neuromodulation.In addition,we discuss recent advances in mid-infrared optical neuromodulation.
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 the National Natural Science Foundation of China (52262020)the Science and Technology Foundation of Guizhou Province (ZK[2021]yiban 328)。
文摘Herein,double-perovskite Ba_(2)LaTaO_(6) Eu-doped orange-red phosphors were successfully synthesized using a high-temperature solid-phase method.The phosphor phase purity was investigated using X-ray diffraction and microscopic morphology analyses.Their luminescence properties were investigated using absorption,emission,excitation,and temperature-dependent spectra.The transition mechanism mainly involves a magnetic-dipole transition with an energy transfer mode featuring multipole-multipole interactions,and concentration quenching is achieved via dipole-dipole interactions.In addition,the intensity of the temperature-dependent spectrum increases abnormally between 298 and 373 K,with the luminous intensity at 373 K increasing to 110%of that observed at room temperature.This phenomenon can be attributed to lattice defects in Ba_(2)LaTaO_(6):Eu^(3+),and the phosphor luminous intensity at473 K remains at 80.62%of that at room temperature.In addition,white-light-emitting diode devices based on this novel Ba_(2)LaTaO_(6):0.35Eu^(3+)phosphor were fabricated to evaluate the potential applications of the as-prepared phosphor.
