Although significant progress has been made in the development of red phosphors,the development of efficient and thermally stable red phosphors remains a challenge.In this paper,(Sr_(3-y)Cay)Ca_(1-x)Nb_(2)O_(9):xSm^(3...Although significant progress has been made in the development of red phosphors,the development of efficient and thermally stable red phosphors remains a challenge.In this paper,(Sr_(3-y)Cay)Ca_(1-x)Nb_(2)O_(9):xSm^(3+)phosphors with 648 nm red emission,which belongs to the ^(4)G_(5/2)→^(6)H_(9/2) leap of Sm^(3+)and is close to the absorption wavelengths of plant chloro phylls and photochromes PR,were prepared by the high-temperature solid-phase method.The lattice mismatch between Sm^(3+)and Ca^(2+)is solved by cation substitution,which increases the atomic disorder and lattice distortion,and the lattice distortion also causes the forbidden leap to be disrupted,thus improving the luminescence efficiency.Meanwhile,the substitution of small-radius cations leads to the enhancement of the structural rigidity of the material.The test results show that after the introduction of Ca^(2+),the luminous intensity of the phosphor is increased by 5.15 times,the quantum yield is increased from 22.89%to 48.31%,and the I_(423 K)/I_(298 K) value is increased from 70.7%to 73.4%,and the fluorescence lifetime is also improved accordingly.White light-emitting diodes(WLEDs)and fuchsia light-emitting diodes(LEDs)were successfully prepared using the experimentally prepared phosphors,demonstrating their great potential in the fields of optical thermometers,WLEDs and plant growth.展开更多
Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material ...Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material was successfully synthesized and Er^(3+)ions were successfully doped into the main lattice.This doping does change the basic structure of the crystal.BaLaGaO_(4):Er^(3+)phosphor exhibits bright green emission centered at 545 nm when excited by 381 nm ultraviolet light or 980 nm near-infrared light.The optimal doping concentration is found to be x=0.04.To quantify the temperature sensitivity of the phosphor,the fluorescence intensity ratio method was used.Within the temperature range of 298-473 K,the maximum relative sensitivities are 1.35%/K(298 K,381 nm)and 1.45%/K(298 K,980 nm),respectively.The maximum absolute sensitivities are 0.67%/K(473 K,381 nm)and 0.69%/K(473 K,980 nm),respectively.Finally,white light-emitting diodes(WLEDs)with a high colour index of Ra=82and a relatively low correlated colour temperature of CCT=5064 K are obtained by integrating the synthesized BaLaGaO_(4):0.04Er^(3+)green phosphor into warm WLEDs devices.These results suggest that Er^(3+)-activated BaLaGaO_(4)multifunctional phosphors hold considerable promise in the areas of optical temperature sensing and WLEDs phosphor conversion.展开更多
In this study,a novel Ca_(2)GaTaO_(6):Sm^(3+)phosphor was developed using the conventional hightemperature solid-phase method.The phase structure and morphology test results of phosphor indicate that the Ca_(2)GaTaO_(...In this study,a novel Ca_(2)GaTaO_(6):Sm^(3+)phosphor was developed using the conventional hightemperature solid-phase method.The phase structure and morphology test results of phosphor indicate that the Ca_(2)GaTaO_(6):Sm^(3+)material was successfully synthesized and the Sm^(3+)ions were successfully doped into the host lattice.When utilizing 406 nm excitation,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor has the strongest emission intensity at 599 nm and shows orange-red emission,which is mainly owing to the^(4)G_(5/2)→^(6)H_(7/2)jump of Sm^(3+)ions.For the performance of different concentrations of Sm^(3+)ions,3 mol%performs the best.At this time,concentration quenching occurs,which is most predominantly induced by dipole-dipole(d-d)interactions.In terms of thermal stability,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor shows good properties,with the luminescence intensity at 423 K exhibiting 88.17%of that at 298 K.The white light-emitting diodes(WLEDs)devices prepared using Ca_(2)GaTaO_(6):Sm^(3+):0.03Sm^(3+)phosphor shows warm white light with excellent performance in terms of correlated color temperature and color rendering index(CCT=3642 K,CRI,Ra=93.5).In terms of anticounterfeit inks,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor also shows good potential.These research results show that Ca_(2)GaTaO_(6):Sm^(3+)phosphors have great performance for application in WLEDs and anti-counterfeit inks.展开更多
Optical thermometry has attracted great attention because it enables accurate temperature measurement in harsh environments due to non-contact temperature measurement.Three-dimensional(3D)lead-free halide perovskites ...Optical thermometry has attracted great attention because it enables accurate temperature measurement in harsh environments due to non-contact temperature measurement.Three-dimensional(3D)lead-free halide perovskites have a great application potential in this field,due to its outstanding luminous properties and stability.In this work,the Sb^(3+)and Er^(3+)are introduced in Cs_(2)NaYCl_(6)double perovskites(DPs).The Sb^(3+)doping Cs_(2)NaYCl_(6)DPs exhibits bright blue emission from the Sb^(3+)activated self-trapped excitons(STEs) and Sb^(3+),Er^(3+)co-doped Cs_(2)NaYCl_(6)has efficient green emission with excellent photo luminescence quantum yields(PLQY) of 81.1% because of the presence of energy transfer from self-trapped excitons to Er^(3+)ions.Excitingly,the ratio between the fluorescence intensity at 524and 550 nm(FIR(I524 nm/I550 nm)) and the ratio between the fluorescence intensity at 524 and 456 nm(FIR(I524 nm/I456 nm)) both have a high correlation with temperature in the range of 298-473 K.The maximum of relative sensitivity values reach to 1.18%/K(I524 nm/I550 nm) and 1.19%/K(I524 nm/I456 nm) at298 K,respectively.The outstanding temperature sensitivity suggests that the Sb^(3+),Er^(3+)co-doped Cs_(2)NaYCl_(6)has enormous application potential in ratio metric optical thermometry.展开更多
Novel orange-red Sr_(2)GdSbO_(6):xEu^(3+)(x=0,0.05,0.1,0.2,0.3,0.4,0.5 and 0.6) phospho rs were successfully prepared by the traditional high-temperature solid-state method.The results of Rietveld refinement,energy di...Novel orange-red Sr_(2)GdSbO_(6):xEu^(3+)(x=0,0.05,0.1,0.2,0.3,0.4,0.5 and 0.6) phospho rs were successfully prepared by the traditional high-temperature solid-state method.The results of Rietveld refinement,energy dispersive spectroscopy(EDS) spectrum and elemental mapping demonstrate that Eu^(3+) successfully replaces the Gd^(3+) sites and distributes uniformly in the particles of phosphors.The luminescence properties of Sr_(2)GdSbO_(6):Eu_(3+)phosphors were investigated in detail.The emission spectra of the strongest emission peak is the ^(5)D_(0)→^(7)F_(1)(593 nm) transition,which can emit orange-red light under393 nm excitation.When the doping concentration of Eu3+ions is x=0.2,the luminescence intensity of the phosphors reaches the highest.The detailed mechanism of concentration quenching is attributed to dipole-dipole interaction.The thermal stability values of Sr_(2)GdSbO_(6):0.2Eu^(3+) phosphors are 87%,82% and114% under 393,467 and 527 nm excitations,respectively.The causes of the abnormal thermal quenching under 527 nm excitation were analyzed.Based on the abnormal thermal quenching under527 nm excitation,the optical thermometry properties of Sr_(2)GdSbO_(6):0.2Eu^(3+)phosphors were investigated by fluorescence intensity ratio(FIR) technique,and appreciable relative sensitivity was obtained.The results suggest that Sr_(2)GdSbO_(6):0.2Eu^(3+)phosphors can be potentially applied to w-LEDs and optical thermometers.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
The work focuses on the utilization of the conventional solid-state sintering procedure to synthesize white phosphors Ca_(2)InTaO_(6):xDy^(3+)(0.02≤x≤0.12).Utilizing X-ray diffraction,the phase structure of samples ...The work focuses on the utilization of the conventional solid-state sintering procedure to synthesize white phosphors Ca_(2)InTaO_(6):xDy^(3+)(0.02≤x≤0.12).Utilizing X-ray diffraction,the phase structure of samples was examined,and the crystal structure was refined using the Rietveld method.A scanning electron microscope was used to analyze the microstructure of sample.First-principles calculations confirm that the indirect bandgap of Ca_(2)InTaO_(6)is 3.786 eV,The luminous properties and energy transfer mechanism of Ca_(2)InTaO_(6):xDy^(3+)were studied using photoluminescence spectroscopy.The^(4)F_(9/2)→^(6)H_(13/2)transition of Dy^(3+)ions is responsible for the greatest emission peak,which was measured at 575 nm.According to research,the lifespan falls as the concentration of Dy^(3+)doping amount rises because of frequent interaction and ene rgy transfer between Dy^(3+)ions.The correlated color temperature of the WLEDs packaged with Ca_(2)InTaO_(6):0.08Dy^(3+)is 4677 K and CIE 1931 chromaticity coordinates are(0.3578,0.3831).Meantime,the phosphor also shows outstanding te mperature stability property,which maintains 83.8%of its initial emission intensity at 450 K(activation energy of 0.1467 eV).The W-LEDs retain their performance for 100 min when powered at 3.4 V voltage and 600 mA current,demonstrating the packed W-LEDs'sustaine d operation at high temperatures.展开更多
基金Project supported by the National Natural Science Foundation of China(52403403)Guizhou Provincial Basic Research Program(Natural Science)(Qian ke he ji chu-ZK 20242024 YiBan 095)。
文摘Although significant progress has been made in the development of red phosphors,the development of efficient and thermally stable red phosphors remains a challenge.In this paper,(Sr_(3-y)Cay)Ca_(1-x)Nb_(2)O_(9):xSm^(3+)phosphors with 648 nm red emission,which belongs to the ^(4)G_(5/2)→^(6)H_(9/2) leap of Sm^(3+)and is close to the absorption wavelengths of plant chloro phylls and photochromes PR,were prepared by the high-temperature solid-phase method.The lattice mismatch between Sm^(3+)and Ca^(2+)is solved by cation substitution,which increases the atomic disorder and lattice distortion,and the lattice distortion also causes the forbidden leap to be disrupted,thus improving the luminescence efficiency.Meanwhile,the substitution of small-radius cations leads to the enhancement of the structural rigidity of the material.The test results show that after the introduction of Ca^(2+),the luminous intensity of the phosphor is increased by 5.15 times,the quantum yield is increased from 22.89%to 48.31%,and the I_(423 K)/I_(298 K) value is increased from 70.7%to 73.4%,and the fluorescence lifetime is also improved accordingly.White light-emitting diodes(WLEDs)and fuchsia light-emitting diodes(LEDs)were successfully prepared using the experimentally prepared phosphors,demonstrating their great potential in the fields of optical thermometers,WLEDs and plant growth.
基金supported by the National Natural Science Foundation of China(52403403)Guizhou Provincial Basic Research Program(Natural Science)(Qian ke he ji chu-ZK2024 YiBan 095)。
文摘Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material was successfully synthesized and Er^(3+)ions were successfully doped into the main lattice.This doping does change the basic structure of the crystal.BaLaGaO_(4):Er^(3+)phosphor exhibits bright green emission centered at 545 nm when excited by 381 nm ultraviolet light or 980 nm near-infrared light.The optimal doping concentration is found to be x=0.04.To quantify the temperature sensitivity of the phosphor,the fluorescence intensity ratio method was used.Within the temperature range of 298-473 K,the maximum relative sensitivities are 1.35%/K(298 K,381 nm)and 1.45%/K(298 K,980 nm),respectively.The maximum absolute sensitivities are 0.67%/K(473 K,381 nm)and 0.69%/K(473 K,980 nm),respectively.Finally,white light-emitting diodes(WLEDs)with a high colour index of Ra=82and a relatively low correlated colour temperature of CCT=5064 K are obtained by integrating the synthesized BaLaGaO_(4):0.04Er^(3+)green phosphor into warm WLEDs devices.These results suggest that Er^(3+)-activated BaLaGaO_(4)multifunctional phosphors hold considerable promise in the areas of optical temperature sensing and WLEDs phosphor conversion.
基金supported by Guizhou Provincial Basic Research Program(Natural Science)(Qian ke he ji chu-ZK2024 YiBan 095)。
文摘In this study,a novel Ca_(2)GaTaO_(6):Sm^(3+)phosphor was developed using the conventional hightemperature solid-phase method.The phase structure and morphology test results of phosphor indicate that the Ca_(2)GaTaO_(6):Sm^(3+)material was successfully synthesized and the Sm^(3+)ions were successfully doped into the host lattice.When utilizing 406 nm excitation,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor has the strongest emission intensity at 599 nm and shows orange-red emission,which is mainly owing to the^(4)G_(5/2)→^(6)H_(7/2)jump of Sm^(3+)ions.For the performance of different concentrations of Sm^(3+)ions,3 mol%performs the best.At this time,concentration quenching occurs,which is most predominantly induced by dipole-dipole(d-d)interactions.In terms of thermal stability,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor shows good properties,with the luminescence intensity at 423 K exhibiting 88.17%of that at 298 K.The white light-emitting diodes(WLEDs)devices prepared using Ca_(2)GaTaO_(6):Sm^(3+):0.03Sm^(3+)phosphor shows warm white light with excellent performance in terms of correlated color temperature and color rendering index(CCT=3642 K,CRI,Ra=93.5).In terms of anticounterfeit inks,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor also shows good potential.These research results show that Ca_(2)GaTaO_(6):Sm^(3+)phosphors have great performance for application in WLEDs and anti-counterfeit inks.
基金Project supported by the National Natural Science Foundation of China (52262020)。
文摘Optical thermometry has attracted great attention because it enables accurate temperature measurement in harsh environments due to non-contact temperature measurement.Three-dimensional(3D)lead-free halide perovskites have a great application potential in this field,due to its outstanding luminous properties and stability.In this work,the Sb^(3+)and Er^(3+)are introduced in Cs_(2)NaYCl_(6)double perovskites(DPs).The Sb^(3+)doping Cs_(2)NaYCl_(6)DPs exhibits bright blue emission from the Sb^(3+)activated self-trapped excitons(STEs) and Sb^(3+),Er^(3+)co-doped Cs_(2)NaYCl_(6)has efficient green emission with excellent photo luminescence quantum yields(PLQY) of 81.1% because of the presence of energy transfer from self-trapped excitons to Er^(3+)ions.Excitingly,the ratio between the fluorescence intensity at 524and 550 nm(FIR(I524 nm/I550 nm)) and the ratio between the fluorescence intensity at 524 and 456 nm(FIR(I524 nm/I456 nm)) both have a high correlation with temperature in the range of 298-473 K.The maximum of relative sensitivity values reach to 1.18%/K(I524 nm/I550 nm) and 1.19%/K(I524 nm/I456 nm) at298 K,respectively.The outstanding temperature sensitivity suggests that the Sb^(3+),Er^(3+)co-doped Cs_(2)NaYCl_(6)has enormous application potential in ratio metric optical thermometry.
基金supported by the National Natural Science Foundation of China (52262020)Guizhou Provincial Department of Education Science and Technology Uprooted Talents Project ([2022] 085)+1 种基金Guizhou Provincial Department of Education Rolling Support for Provincial Universities Scientific Research Platform Team Project ([2022] 036)the Science and Technology Foundation of Guizhou Province (ZK [2021] 328)。
文摘Novel orange-red Sr_(2)GdSbO_(6):xEu^(3+)(x=0,0.05,0.1,0.2,0.3,0.4,0.5 and 0.6) phospho rs were successfully prepared by the traditional high-temperature solid-state method.The results of Rietveld refinement,energy dispersive spectroscopy(EDS) spectrum and elemental mapping demonstrate that Eu^(3+) successfully replaces the Gd^(3+) sites and distributes uniformly in the particles of phosphors.The luminescence properties of Sr_(2)GdSbO_(6):Eu_(3+)phosphors were investigated in detail.The emission spectra of the strongest emission peak is the ^(5)D_(0)→^(7)F_(1)(593 nm) transition,which can emit orange-red light under393 nm excitation.When the doping concentration of Eu3+ions is x=0.2,the luminescence intensity of the phosphors reaches the highest.The detailed mechanism of concentration quenching is attributed to dipole-dipole interaction.The thermal stability values of Sr_(2)GdSbO_(6):0.2Eu^(3+) phosphors are 87%,82% and114% under 393,467 and 527 nm excitations,respectively.The causes of the abnormal thermal quenching under 527 nm excitation were analyzed.Based on the abnormal thermal quenching under527 nm excitation,the optical thermometry properties of Sr_(2)GdSbO_(6):0.2Eu^(3+)phosphors were investigated by fluorescence intensity ratio(FIR) technique,and appreciable relative sensitivity was obtained.The results suggest that Sr_(2)GdSbO_(6):0.2Eu^(3+)phosphors can be potentially applied to w-LEDs and optical thermometers.
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.
基金Project supported by the Science and Technology Foundation of Guizhou Province(20201Y271)。
文摘The work focuses on the utilization of the conventional solid-state sintering procedure to synthesize white phosphors Ca_(2)InTaO_(6):xDy^(3+)(0.02≤x≤0.12).Utilizing X-ray diffraction,the phase structure of samples was examined,and the crystal structure was refined using the Rietveld method.A scanning electron microscope was used to analyze the microstructure of sample.First-principles calculations confirm that the indirect bandgap of Ca_(2)InTaO_(6)is 3.786 eV,The luminous properties and energy transfer mechanism of Ca_(2)InTaO_(6):xDy^(3+)were studied using photoluminescence spectroscopy.The^(4)F_(9/2)→^(6)H_(13/2)transition of Dy^(3+)ions is responsible for the greatest emission peak,which was measured at 575 nm.According to research,the lifespan falls as the concentration of Dy^(3+)doping amount rises because of frequent interaction and ene rgy transfer between Dy^(3+)ions.The correlated color temperature of the WLEDs packaged with Ca_(2)InTaO_(6):0.08Dy^(3+)is 4677 K and CIE 1931 chromaticity coordinates are(0.3578,0.3831).Meantime,the phosphor also shows outstanding te mperature stability property,which maintains 83.8%of its initial emission intensity at 450 K(activation energy of 0.1467 eV).The W-LEDs retain their performance for 100 min when powered at 3.4 V voltage and 600 mA current,demonstrating the packed W-LEDs'sustaine d operation at high temperatures.
基金supported by the Science and Technology Foundation of Guizhou Province(ZK[2021]yiban 328)the Postgraduate Education Innovation Program in Guizhou Province(YJSCXJH(2021)202)。
