A series of single phase,warm white light emitting phosphors,Gd(P_(x)V_(1−x))O_(4):y at%Sm^(3+),with 1 at%Bi^(3+) doping concentration were synthesized by high temperature solid state method in this work.The experimen...A series of single phase,warm white light emitting phosphors,Gd(P_(x)V_(1−x))O_(4):y at%Sm^(3+),with 1 at%Bi^(3+) doping concentration were synthesized by high temperature solid state method in this work.The experimental results indicate broadband cyan emission of Bi^(3+)and characteristic orange-red emission of Sm^(3+)can be effectively tuned by changing the ratios of PO^(3−)_(4)/VO^(3−)_(4) in Gd(P_(x)V_(1−x))O_(4):1 at%Sm^(3+),1 at%Bi^(3+),and the energy transfer process among VO^(3−)_(4),Sm^(3+),Bi^(3+) also can be adjusted.Based on this,warm white light emitting can be realized by further optimizing the doping concentration of Sm^(3+) in the phosphors.At 423 K,the PL intensity of Gd(P_(0.7)V_(0.3))O_(4):2 at%Sm^(3+),1 at%Bi^(3+) remains~84.3%of the initial value at 293 K,while the measured quantum efficiency is 67.8%.EL spectrum analysis results of the fabricated white light emitting diode(wLED)based on a 310 nm UV-chip and Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)phosphors imply low correlated color temperature(3132 K)and appropriate color-rending index(R_(a)=82.7).These results demonstrate that Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)is a good candidate for manufacturing UV-activated warm white light emitting diodes.展开更多
A series of uniform single-phase spherical BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors were prepared via a microwave hydrothermal method by using trisodium citrate dehydrate as surfactant.The phase structure,morphology an...A series of uniform single-phase spherical BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors were prepared via a microwave hydrothermal method by using trisodium citrate dehydrate as surfactant.The phase structure,morphology and photoluminescence properties were measured by powder X-ray diffraction,scanning electron microscope and fluorescence spectrometer,respectively.The results show that uniform spherical microcrystals with diameters in the range of 2–4μm are obtained.And the phase and morphology of samples are not significantly changed by doping rare earth(RE^(3+))ions.Under the excitation wavelength of 356 and 365 nm,the samples BaWO 4:0.03Dy^(3+),yTm^(3+)can emit cold white light.In order to lower the correlated color temperature(CCT)to get a warm white light,the Eu^(3+)ions were doped into BaWO 4:0.03Dy^(3+),0.01Tm^(3+).Especially,under the excitation of 365 nm,BaWO 4:0.03Dy^(3+),0.01Tm^(3+),0.03Eu^(3+)phosphor shew a bright warm white light with color coordi-nate of(0.4013,0.3629)and CCT of 3288 K.Moreover,in the BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors,the energy transfer mechanism among Dy^(3+),Tm^(3+)and Eu^(3+)ions have been discussed and the change of electron structures have been calculated by first-principles calculations.The results shew that the uniform single-phase spherical BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors could be favorable candidates in warm white LEDs.展开更多
The novel single Dy^(3+)-activated and Dy^(3+)/Eu^(3+)co-activated LaSr_(2)F_(7) NPs-based phosphors were successfully synthesized via a simple precipitation reaction method at room temperature.The phase formations an...The novel single Dy^(3+)-activated and Dy^(3+)/Eu^(3+)co-activated LaSr_(2)F_(7) NPs-based phosphors were successfully synthesized via a simple precipitation reaction method at room temperature.The phase formations and cell parameters of single Dy^(3+)-activated and Dy^(3+)/Eu^(3+)co-activated LaSr_(2)F_(7) NPs were verified in detail by the Rietveld refinement technique based on the recorded X-ray diffraction patterns.The doping concentration of single Dy^(3+)-activated LaSr_(2)F_(7) NPs was optimized to be 0.1 mol with the concentration quenching dominated by the electric dipole-dipole interaction.Meanwhile,a variety of Eu^(3+)-activated La_(0.9)Sr_(2)F_(7):0.1Dy^(3+)NPs exhibited tunable luminescent properties and emitted warm white light in close to standard warm white light under 363 nm excitation.The valid energy transfer(ET)efficiency from Dy^(3+) to Eu^(3+) ions was estimated to be about 86.02%based on the emission intensity while the electric dipole-quadrupole interaction dominated the concentration quenching mechanism in ET process.Eventually,the thermal quenching of the obtained samples was studied,showing the excellent thermal stability.All the results manifest that Eu^(3+)-activated LaSr_(2)F_(7):Dy^(3+)NPs could emit warm white light with excellent thermal stability for indoor illumination.展开更多
采用逐步热注射法合成了用于白光LED的Cu In S2/Zn S(CIS/Zn S)核壳结构量子点。通过调整Cu/In的比率,在Cu In S2(CIS)量子点的基础上,合成了发射波长在570~650 nm之间可调的CIS/Zn S量子点。与CIS量子点的低量子产率相比,具有核壳结构...采用逐步热注射法合成了用于白光LED的Cu In S2/Zn S(CIS/Zn S)核壳结构量子点。通过调整Cu/In的比率,在Cu In S2(CIS)量子点的基础上,合成了发射波长在570~650 nm之间可调的CIS/Zn S量子点。与CIS量子点的低量子产率相比,具有核壳结构的CIS/Zn S量子点的量子产率达到了78%。通过在黄光荧光粉YAG∶Ce3+表面旋涂CIS/Zn S量子点的方式制备了暖白光LED器件。在工作电流为10 m A时,暖白光LED的发光效率达到了244.58 lm/W。由于CIS/Zn S量子点的加入,所制备的白光LED器件的显色指数达到86.7且发光颜色向暖色调发生了转移,相应的色坐标为(0.340 6,0.369 0)。展开更多
以Bi_2O_3-B_2O_3-ZnO为基质玻璃的原料组分,制备工艺采用传统的熔融冷却法,溶制温度950℃制备出基质玻璃。再通过低温共烧结法在基质玻璃中成功掺入Lu_(2.94-x)Y_XAl_5O_(12):0.06Ce(X=0~0.8)绿色荧光粉制备出绿色荧光玻璃。利用stc-4...以Bi_2O_3-B_2O_3-ZnO为基质玻璃的原料组分,制备工艺采用传统的熔融冷却法,溶制温度950℃制备出基质玻璃。再通过低温共烧结法在基质玻璃中成功掺入Lu_(2.94-x)Y_XAl_5O_(12):0.06Ce(X=0~0.8)绿色荧光粉制备出绿色荧光玻璃。利用stc-4000快速光谱仪和PMS-80可见光谱分析系统研究了不同电流下的LED器件光效、色温、色坐标的变化情况。结果表明,随着驱动电流从10 m A逐渐升高到30 m A,LED器件的测试光效大约下降16%,相关色温变化较小,色坐标未发生漂移。由于缺少红光成分,实验在绿色荧光玻璃上通过旋转涂覆一层红色荧光薄膜制备出高显色指数的暖白光LED,进一步推动绿色荧光玻璃在白光LED中的应用。展开更多
基金Project supported by the National Natural Science Foundation of China(51972181,61705231)Major Basic Research Projects of Shandong Natural Science Foundation(ZR2018ZB0650)+2 种基金China Postdoctoral Science Foundation(2015M580573)High Quality Course Construction Project of Graduate Education in Shandong Province(SDYKC18051)Postgraduate Tutor Ability Improvement Project of Shandong Province(SDYY17179)。
文摘A series of single phase,warm white light emitting phosphors,Gd(P_(x)V_(1−x))O_(4):y at%Sm^(3+),with 1 at%Bi^(3+) doping concentration were synthesized by high temperature solid state method in this work.The experimental results indicate broadband cyan emission of Bi^(3+)and characteristic orange-red emission of Sm^(3+)can be effectively tuned by changing the ratios of PO^(3−)_(4)/VO^(3−)_(4) in Gd(P_(x)V_(1−x))O_(4):1 at%Sm^(3+),1 at%Bi^(3+),and the energy transfer process among VO^(3−)_(4),Sm^(3+),Bi^(3+) also can be adjusted.Based on this,warm white light emitting can be realized by further optimizing the doping concentration of Sm^(3+) in the phosphors.At 423 K,the PL intensity of Gd(P_(0.7)V_(0.3))O_(4):2 at%Sm^(3+),1 at%Bi^(3+) remains~84.3%of the initial value at 293 K,while the measured quantum efficiency is 67.8%.EL spectrum analysis results of the fabricated white light emitting diode(wLED)based on a 310 nm UV-chip and Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)phosphors imply low correlated color temperature(3132 K)and appropriate color-rending index(R_(a)=82.7).These results demonstrate that Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)is a good candidate for manufacturing UV-activated warm white light emitting diodes.
基金This work was supported by Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.
文摘A series of uniform single-phase spherical BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors were prepared via a microwave hydrothermal method by using trisodium citrate dehydrate as surfactant.The phase structure,morphology and photoluminescence properties were measured by powder X-ray diffraction,scanning electron microscope and fluorescence spectrometer,respectively.The results show that uniform spherical microcrystals with diameters in the range of 2–4μm are obtained.And the phase and morphology of samples are not significantly changed by doping rare earth(RE^(3+))ions.Under the excitation wavelength of 356 and 365 nm,the samples BaWO 4:0.03Dy^(3+),yTm^(3+)can emit cold white light.In order to lower the correlated color temperature(CCT)to get a warm white light,the Eu^(3+)ions were doped into BaWO 4:0.03Dy^(3+),0.01Tm^(3+).Especially,under the excitation of 365 nm,BaWO 4:0.03Dy^(3+),0.01Tm^(3+),0.03Eu^(3+)phosphor shew a bright warm white light with color coordi-nate of(0.4013,0.3629)and CCT of 3288 K.Moreover,in the BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors,the energy transfer mechanism among Dy^(3+),Tm^(3+)and Eu^(3+)ions have been discussed and the change of electron structures have been calculated by first-principles calculations.The results shew that the uniform single-phase spherical BaWO 4:Dy^(3+),Tm^(3+),Eu^(3+)phosphors could be favorable candidates in warm white LEDs.
基金the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIP)(No.2018R1A6A1A03025708)。
文摘The novel single Dy^(3+)-activated and Dy^(3+)/Eu^(3+)co-activated LaSr_(2)F_(7) NPs-based phosphors were successfully synthesized via a simple precipitation reaction method at room temperature.The phase formations and cell parameters of single Dy^(3+)-activated and Dy^(3+)/Eu^(3+)co-activated LaSr_(2)F_(7) NPs were verified in detail by the Rietveld refinement technique based on the recorded X-ray diffraction patterns.The doping concentration of single Dy^(3+)-activated LaSr_(2)F_(7) NPs was optimized to be 0.1 mol with the concentration quenching dominated by the electric dipole-dipole interaction.Meanwhile,a variety of Eu^(3+)-activated La_(0.9)Sr_(2)F_(7):0.1Dy^(3+)NPs exhibited tunable luminescent properties and emitted warm white light in close to standard warm white light under 363 nm excitation.The valid energy transfer(ET)efficiency from Dy^(3+) to Eu^(3+) ions was estimated to be about 86.02%based on the emission intensity while the electric dipole-quadrupole interaction dominated the concentration quenching mechanism in ET process.Eventually,the thermal quenching of the obtained samples was studied,showing the excellent thermal stability.All the results manifest that Eu^(3+)-activated LaSr_(2)F_(7):Dy^(3+)NPs could emit warm white light with excellent thermal stability for indoor illumination.
文摘以Bi_2O_3-B_2O_3-ZnO为基质玻璃的原料组分,制备工艺采用传统的熔融冷却法,溶制温度950℃制备出基质玻璃。再通过低温共烧结法在基质玻璃中成功掺入Lu_(2.94-x)Y_XAl_5O_(12):0.06Ce(X=0~0.8)绿色荧光粉制备出绿色荧光玻璃。利用stc-4000快速光谱仪和PMS-80可见光谱分析系统研究了不同电流下的LED器件光效、色温、色坐标的变化情况。结果表明,随着驱动电流从10 m A逐渐升高到30 m A,LED器件的测试光效大约下降16%,相关色温变化较小,色坐标未发生漂移。由于缺少红光成分,实验在绿色荧光玻璃上通过旋转涂覆一层红色荧光薄膜制备出高显色指数的暖白光LED,进一步推动绿色荧光玻璃在白光LED中的应用。
