The BaGd（2-2 x）Eu（2 x）O4（BG, x = 0.01-0.09） phosphors were successfully synthesized via the sol-gel method,and BaY（2-2 y）Eu（2 y）O4（BY, y = 0.005-0.07） phosphors were included for comparison. The pure phase...The BaGd（2-2 x）Eu（2 x）O4（BG, x = 0.01-0.09） phosphors were successfully synthesized via the sol-gel method,and BaY（2-2 y）Eu（2 y）O4（BY, y = 0.005-0.07） phosphors were included for comparison. The pure phase BG phosphors with the ordered CaFe2 O4-type structure are obtained by annealing at 1300℃ for5 h. The phosphors with uniform particle size of 120 nm and good dispersion display typical Eu^3＋emission with the strongest peak at 613 nm（^5 D0→^7 F2 transition of Eu3＋） under optimal excitation band at 262 nm（CTB band）. The presence of Gd^3＋ excitation bands on the PLE spectra monitoring the Eu3＋emission directly proves an evidence of Gd^3＋-Eu^3＋ energy transfer. Owing to the concentration quenching, the optimum content of Eu3＋ addition is 5 at%（x = 0.05）, and the quenching mechanism is determined to be the exchange reaction between Eu3＋. All the BG samples have similar color coordinates and temperature of（0.64 ± 0.02, 0.36 ± 0.01） and 2000 ± 100 K,respectively. The lifetime value of BaGd（1.9）Eu（0.1）O4 for 613 nm is fitted to be 2.19 ± 0.01 ms, and the Eu^3＋ concentration does not change the lifetime significantly. Owing to the Gd^3＋-Eu^3＋ energy transfer, the luminescent intensity of the BaGd（1.9）Eu（0.1）O4 phosphor is better than BY system. The BG system served as a new type of phosphor is expected to be widely used in lighting and display areas.展开更多
The average photoelectric conversion efficiency(PCE)of a bare mono crystalline silicon solar cell is 14.71%±0.03%under AM1.5.It decreases to 14.20%±0.005%when covering an un-doped flat glass on the solar cel...The average photoelectric conversion efficiency(PCE)of a bare mono crystalline silicon solar cell is 14.71%±0.03%under AM1.5.It decreases to 14.20%±0.005%when covering an un-doped flat glass on the solar cell,and it goes down to 14.10%±0.005%by using a 5 wt%Eu^3+doped glass.The absorptions of the Eu^3+doped CPM glass one-to-one match the excitation spectra at 362,381,393,400,413 and464 nm,which are related to the transitions of 7 F0→(5 D4,5 G2,5 L6,5 D3),7 F1→5 D3,and 7 F0→5 D2,respectively.In addition,a concave pyramid microstructure(CPM)is embedded in the glass surface to increase light transmittance.The average PCE increases to 14.61%±0.07%when a 5 wt%Eu^3+doped CPM glass covers on the silicon solar cell.Compared with the un-doped flat glass,a net increase of the PCE is0.41%,where the 0.16%increment of PCE is from the lighting trapping of the CPM structure,and the downshifting of near ultraviolet(NUV)light by Eu^3+ion donates the other 0.25%increment.It confirms that the as-prepared Eu^3+doped CPM glass has a good downshifting and antireflection function.展开更多
A Eu^3＋-doped CaCO3 phosphor with red emission was prepared by microwave synthesis. The scanning electron microscopy （SEM） image and laser particle size analysis show that the CaCO3：Eu^3＋ particles are needle-lik...A Eu^3＋-doped CaCO3 phosphor with red emission was prepared by microwave synthesis. The scanning electron microscopy （SEM） image and laser particle size analysis show that the CaCO3：Eu^3＋ particles are needle-like in the length range of 5.0-10.0 μm. The results of X-ray diffraction （XRD） analysis, Fourier transform infrared spectroscopy （FT-IR）, and Raman spectroscopy indicate that pure aragonite CaCO3：Eu^3＋ is prepared using microwave irradiation and the Eu^3＋ ion as a luminescence center inhabits the site of Ca^2＋. The photoluminescence excitation （PLE） spectrum shows that the strong broad band at around 270 nm and weak sharp lines in 300-550 nm are assigned to the charge transfer band of Eu^3＋-O^2- and intra-configurational 4f-4f transitions of Eu^3＋, respectively. The photoluminescence （PL） spectrum implies that the red luminescence can be attributed to the transitions from the ^5D0 excited level to the ^7FJ （J = 0, 1, 2, 3, 4） levels of Eu^3＋ ions with the mainly electric dipole transition ^5D0 → ^7F2 （614 and 620 nm）, and the Eu^3＋ ions prefer to occupy the low symmetric site in the crystal lattice.展开更多
SrMoO4：Eu^3＋（10%） phosphors were produced via hydrothermal synthesis and co-precipitation.We systematically analyzed how the morphology and luminescence properties of the phosphors were affected by the synthesis c...SrMoO4：Eu^3＋（10%） phosphors were produced via hydrothermal synthesis and co-precipitation.We systematically analyzed how the morphology and luminescence properties of the phosphors were affected by the synthesis conditions,including the p H of the precursor solution,stirring speed,and postsintering temperature.The samples synthesized at p H = 8 and 9 were spindle-like rods with a core-shell structure.When the stirring speed increased to Vs = 150 r/min,the core-shell structure disappeared.Photoluminescence measurements indicated that the Sr Mo O4：Eu^3＋samples under ultraviolet radiation produced strong red emission centered at 616 nm.The luminescence properties were greatly affected by the p H,stirring during hydrothermal reaction,and use of post-annealing.The related mechansim is discussed.展开更多
基金Project supported by the National Natural Science Foundation of China(51402125)China Postdoctoral Science Foundation(2017M612175)+3 种基金the Special Fund for the Postdoctoral Innovation Project in Shandong Province(201603061)the Research Fund for the Doctoral Program of University of Jinan(XBS1447)the Natural Science Foundation of University of Jinan(XKY1515)the Science Foundation for Post Doctorate Research from the University of Jinan(XBH1607)
文摘The BaGd（2-2 x）Eu（2 x）O4（BG, x = 0.01-0.09） phosphors were successfully synthesized via the sol-gel method,and BaY（2-2 y）Eu（2 y）O4（BY, y = 0.005-0.07） phosphors were included for comparison. The pure phase BG phosphors with the ordered CaFe2 O4-type structure are obtained by annealing at 1300℃ for5 h. The phosphors with uniform particle size of 120 nm and good dispersion display typical Eu^3＋emission with the strongest peak at 613 nm（^5 D0→^7 F2 transition of Eu3＋） under optimal excitation band at 262 nm（CTB band）. The presence of Gd^3＋ excitation bands on the PLE spectra monitoring the Eu3＋emission directly proves an evidence of Gd^3＋-Eu^3＋ energy transfer. Owing to the concentration quenching, the optimum content of Eu3＋ addition is 5 at%（x = 0.05）, and the quenching mechanism is determined to be the exchange reaction between Eu3＋. All the BG samples have similar color coordinates and temperature of（0.64 ± 0.02, 0.36 ± 0.01） and 2000 ± 100 K,respectively. The lifetime value of BaGd（1.9）Eu（0.1）O4 for 613 nm is fitted to be 2.19 ± 0.01 ms, and the Eu^3＋ concentration does not change the lifetime significantly. Owing to the Gd^3＋-Eu^3＋ energy transfer, the luminescent intensity of the BaGd（1.9）Eu（0.1）O4 phosphor is better than BY system. The BG system served as a new type of phosphor is expected to be widely used in lighting and display areas.
基金Project supported by National"Double First-class"Construction Special Funding Project(0290-X2100502)。
文摘The average photoelectric conversion efficiency(PCE)of a bare mono crystalline silicon solar cell is 14.71%±0.03%under AM1.5.It decreases to 14.20%±0.005%when covering an un-doped flat glass on the solar cell,and it goes down to 14.10%±0.005%by using a 5 wt%Eu^3+doped glass.The absorptions of the Eu^3+doped CPM glass one-to-one match the excitation spectra at 362,381,393,400,413 and464 nm,which are related to the transitions of 7 F0→(5 D4,5 G2,5 L6,5 D3),7 F1→5 D3,and 7 F0→5 D2,respectively.In addition,a concave pyramid microstructure(CPM)is embedded in the glass surface to increase light transmittance.The average PCE increases to 14.61%±0.07%when a 5 wt%Eu^3+doped CPM glass covers on the silicon solar cell.Compared with the un-doped flat glass,a net increase of the PCE is0.41%,where the 0.16%increment of PCE is from the lighting trapping of the CPM structure,and the downshifting of near ultraviolet(NUV)light by Eu^3+ion donates the other 0.25%increment.It confirms that the as-prepared Eu^3+doped CPM glass has a good downshifting and antireflection function.
基金supported by the National Natural Science Foundation of China (No. 10476024) the Science and Technology Bureau of Sichuan Province, China (No. 2006J13-059)
文摘A Eu^3＋-doped CaCO3 phosphor with red emission was prepared by microwave synthesis. The scanning electron microscopy （SEM） image and laser particle size analysis show that the CaCO3：Eu^3＋ particles are needle-like in the length range of 5.0-10.0 μm. The results of X-ray diffraction （XRD） analysis, Fourier transform infrared spectroscopy （FT-IR）, and Raman spectroscopy indicate that pure aragonite CaCO3：Eu^3＋ is prepared using microwave irradiation and the Eu^3＋ ion as a luminescence center inhabits the site of Ca^2＋. The photoluminescence excitation （PLE） spectrum shows that the strong broad band at around 270 nm and weak sharp lines in 300-550 nm are assigned to the charge transfer band of Eu^3＋-O^2- and intra-configurational 4f-4f transitions of Eu^3＋, respectively. The photoluminescence （PL） spectrum implies that the red luminescence can be attributed to the transitions from the ^5D0 excited level to the ^7FJ （J = 0, 1, 2, 3, 4） levels of Eu^3＋ ions with the mainly electric dipole transition ^5D0 → ^7F2 （614 and 620 nm）, and the Eu^3＋ ions prefer to occupy the low symmetric site in the crystal lattice.
基金financially supported by the National Natural Science Foundation of China under Grant No.11204001the Anhui Provincial Natural Science Foundation(No.1308085MA04)+3 种基金the Higher Educational Natural Science Foundation of Anhui Province(No.KJ2013A031)supported by Anhui University Scientific Research Fund No.KYXL2013009"211 Project" of Anhui University(No.SZJYKC2013020)the National Training Programs of Innovation and Entrepreneurship for Undergraduates(No.201410357005)
文摘SrMoO4：Eu^3＋（10%） phosphors were produced via hydrothermal synthesis and co-precipitation.We systematically analyzed how the morphology and luminescence properties of the phosphors were affected by the synthesis conditions,including the p H of the precursor solution,stirring speed,and postsintering temperature.The samples synthesized at p H = 8 and 9 were spindle-like rods with a core-shell structure.When the stirring speed increased to Vs = 150 r/min,the core-shell structure disappeared.Photoluminescence measurements indicated that the Sr Mo O4：Eu^3＋samples under ultraviolet radiation produced strong red emission centered at 616 nm.The luminescence properties were greatly affected by the p H,stirring during hydrothermal reaction,and use of post-annealing.The related mechansim is discussed.
