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
An improved sol-gel method was employed to prepare Eu3+ ions doped SiO2-Y2O3 nanocomposites.Systematic study was carried out on the effect of post-annealing treatment on photoluminescence(PL) properties of the samples...An improved sol-gel method was employed to prepare Eu3+ ions doped SiO2-Y2O3 nanocomposites.Systematic study was carried out on the effect of post-annealing treatment on photoluminescence(PL) properties of the samples under various europium ions doping concentrations.X-ray diffraction(XRD) patterns indicated that the samples showed an amorphous matrix structure,and the scanning electron microscopy(SEM) pictures showed that the samples presented a nano size(from 21 to 42 nm) granular-stack structure after hi...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
Undoped and Eu3+-doped Sr2CeO4 luminescent materials were prepared by sol-gel method. The structure and uncommon photoluminescence of Sr2CeO4∶Eu3+ phosphors were investigated in detail by powder X-ray diffraction (XR...Undoped and Eu3+-doped Sr2CeO4 luminescent materials were prepared by sol-gel method. The structure and uncommon photoluminescence of Sr2CeO4∶Eu3+ phosphors were investigated in detail by powder X-ray diffraction (XRD), Raman spectrum, and photoluminescence spectrum, respectively. The XRD results demonstrate that the as-prepared Sr2CeO4 phosphor is single phase and well crystallized. For Sr2CeO4∶Eu3+ phosphor, its excitation spectrum consists of a broad intense band from host and Eu3+-O2-charge transfer and a number of small peaks from Eu3+ ion. The broad emission band originated from Sr2CeO4 host and Eu3+ emission lines in the blue, green, and red regions coexist. Not only the characteristic transition lines from the lowest excited 5D0 level of Eu3+ but also those from higher energy levels 5DJ (J=1, 2) of Eu3+ ions are observed. These unusual luminescence properties result from the low vibration energy of Sr2CeO4 host-lattice and different energy transfer process from host to activator.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supported by the Guangdong Province (2007-173)Jiangmen City (2009-217)
文摘An improved sol-gel method was employed to prepare Eu3+ ions doped SiO2-Y2O3 nanocomposites.Systematic study was carried out on the effect of post-annealing treatment on photoluminescence(PL) properties of the samples under various europium ions doping concentrations.X-ray diffraction(XRD) patterns indicated that the samples showed an amorphous matrix structure,and the scanning electron microscopy(SEM) pictures showed that the samples presented a nano size(from 21 to 42 nm) granular-stack structure after hi...
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National Natural Science Foundation of China(51364024,50364002)Foundation of State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials(SKL 1316)Gansu Province Department of Education Fund(2013A-029)
基金Project supported bythe JSTUFoundation of Science Research (KYY05039)
文摘Undoped and Eu3+-doped Sr2CeO4 luminescent materials were prepared by sol-gel method. The structure and uncommon photoluminescence of Sr2CeO4∶Eu3+ phosphors were investigated in detail by powder X-ray diffraction (XRD), Raman spectrum, and photoluminescence spectrum, respectively. The XRD results demonstrate that the as-prepared Sr2CeO4 phosphor is single phase and well crystallized. For Sr2CeO4∶Eu3+ phosphor, its excitation spectrum consists of a broad intense band from host and Eu3+-O2-charge transfer and a number of small peaks from Eu3+ ion. The broad emission band originated from Sr2CeO4 host and Eu3+ emission lines in the blue, green, and red regions coexist. Not only the characteristic transition lines from the lowest excited 5D0 level of Eu3+ but also those from higher energy levels 5DJ (J=1, 2) of Eu3+ ions are observed. These unusual luminescence properties result from the low vibration energy of Sr2CeO4 host-lattice and different energy transfer process from host to activator.
