A series of novel red-emitting phosphors scheelite-like triple molybdates LiKGd2.xEux（MoO4）4（0.1≤ x ≤ 1.9） were synthesized by solid state reaction method and their photoluminescence properties were investigated...A series of novel red-emitting phosphors scheelite-like triple molybdates LiKGd2.xEux（MoO4）4（0.1≤ x ≤ 1.9） were synthesized by solid state reaction method and their photoluminescence properties were investigated. The photoluminescence results show that all samples can be excited efficiently by UV （396 nm） light and blue （466 nm） light and emit red （615 nm） light with line spectra, which are coupled well with the characteristic emission from UV-LED and blue LED, respectively. The experimental results and their analysis suggest that the energy transfer occurs due to dipole-dipole interactions among Eu3＋ ions in LiKGd2-xEux（MoO4）4. Compared with Cao.8MoO4： Eu0.2^3-, the emission intensity of LiKGdo.9（MoO4）4： Eu1.1^3- is about 1.4 times higher and the CIE chromaticity coordinates are as close to the National Television System Committee （NTSC） standard values as those of Cao.8MoO4： Eu0.2^3-. The optical properties suggest that LiKGdo.9（MoO4）4： Eu1.1^3- is an efficient red-emitting phosphor for white LEDs applications.展开更多
A series of novel red tungsto-molybdate phosphors, LiEul-xSmx（WO4）0.5（MoO4）1.5 （x = 0, 0.25%, 0.50%, 0.75%, 1.00%, 2.00% 4.00%, 6.00%, 8.00% and 10.00%）, were synthesized using conventional solid state reaction ...A series of novel red tungsto-molybdate phosphors, LiEul-xSmx（WO4）0.5（MoO4）1.5 （x = 0, 0.25%, 0.50%, 0.75%, 1.00%, 2.00% 4.00%, 6.00%, 8.00% and 10.00%）, were synthesized using conventional solid state reaction methods. The experimental re- sults indicate that the introduction of Sm^3＋ changes neither the crystal structure nor the shape and position of the emission spectra. However, it extends the excitation region at 400 nm and enhances the emission at 615 nm. The reason for the im- provement of red emission of Eu^3＋ by the introduction of Sm^3＋ and the energy transfer mechanism from Sm^3＋ to Eu^3＋ was in- vestigated in detail.展开更多
A series of new red fluorescent siloles consisting of a silole core and dimesitylboranyl substituent connected with a furan, thiophene, and selenophene bridges were synthesized and characterized. The optical propertie...A series of new red fluorescent siloles consisting of a silole core and dimesitylboranyl substituent connected with a furan, thiophene, and selenophene bridges were synthesized and characterized. The optical properties, electronic structures, and electroluminescence （EL） performances were investigated. The emission wavelengths were red-shifted from the siloles with furan, to those with thiophene, and then selenophene. The thiophene, and selenophene-containing siloles, （MesB）2DTTPS, and （MesB）zDSTPS, showed the typical aggregation-enhanced emission （AEE） feature, while furan-containing one, （MesB）2DFTPS, showed slight emission decrease as the aggregate formation. Theoretical calculations were carried out to explain the difference in the optical properties. Undoped OLEDs using these red siloles as light-emitting layers were fabricated. The device of （MesB）2DTTPS exhibited the best performance. It radiated red EL emission at 589 nm, and afforded good maximum luminance, current, power, and external quantum efficiency of 13300 cd m^-2, 4.3 cd A^-1, 2.9 lm W^-1, and 1.8%, respectively.展开更多
基金supported by the Major Science and Technology Projects of Wuhan City Science and Technology Bureau (Grant No.200810321148)
文摘A series of novel red-emitting phosphors scheelite-like triple molybdates LiKGd2.xEux（MoO4）4（0.1≤ x ≤ 1.9） were synthesized by solid state reaction method and their photoluminescence properties were investigated. The photoluminescence results show that all samples can be excited efficiently by UV （396 nm） light and blue （466 nm） light and emit red （615 nm） light with line spectra, which are coupled well with the characteristic emission from UV-LED and blue LED, respectively. The experimental results and their analysis suggest that the energy transfer occurs due to dipole-dipole interactions among Eu3＋ ions in LiKGd2-xEux（MoO4）4. Compared with Cao.8MoO4： Eu0.2^3-, the emission intensity of LiKGdo.9（MoO4）4： Eu1.1^3- is about 1.4 times higher and the CIE chromaticity coordinates are as close to the National Television System Committee （NTSC） standard values as those of Cao.8MoO4： Eu0.2^3-. The optical properties suggest that LiKGdo.9（MoO4）4： Eu1.1^3- is an efficient red-emitting phosphor for white LEDs applications.
基金supported by the Natural Science Foundation of Fujian Province (Grant No. 2011J05142)the Ministry of Education in China Project of Humanities and Social Sciences (Grant No. 11YJC820135)
文摘A series of novel red tungsto-molybdate phosphors, LiEul-xSmx（WO4）0.5（MoO4）1.5 （x = 0, 0.25%, 0.50%, 0.75%, 1.00%, 2.00% 4.00%, 6.00%, 8.00% and 10.00%）, were synthesized using conventional solid state reaction methods. The experimental re- sults indicate that the introduction of Sm^3＋ changes neither the crystal structure nor the shape and position of the emission spectra. However, it extends the excitation region at 400 nm and enhances the emission at 615 nm. The reason for the im- provement of red emission of Eu^3＋ by the introduction of Sm^3＋ and the energy transfer mechanism from Sm^3＋ to Eu^3＋ was in- vestigated in detail.
基金supported by the National Natural Sci-ence Foundation of China (51273053)the National Basic Research Program of China (2015CB655004,2013CB834702)+3 种基金the Guangdong Natural Science Funds for Distinguished Young Scholar (2014A 030306035)the Guangdong Innovative R esearch Team Program o f China (201101C0105067115)ITC-CN ERC14S01the Fundam ental Research Funds for the Central Univer- sities (2015PT020, 2015ZY013)
文摘A series of new red fluorescent siloles consisting of a silole core and dimesitylboranyl substituent connected with a furan, thiophene, and selenophene bridges were synthesized and characterized. The optical properties, electronic structures, and electroluminescence （EL） performances were investigated. The emission wavelengths were red-shifted from the siloles with furan, to those with thiophene, and then selenophene. The thiophene, and selenophene-containing siloles, （MesB）2DTTPS, and （MesB）zDSTPS, showed the typical aggregation-enhanced emission （AEE） feature, while furan-containing one, （MesB）2DFTPS, showed slight emission decrease as the aggregate formation. Theoretical calculations were carried out to explain the difference in the optical properties. Undoped OLEDs using these red siloles as light-emitting layers were fabricated. The device of （MesB）2DTTPS exhibited the best performance. It radiated red EL emission at 589 nm, and afforded good maximum luminance, current, power, and external quantum efficiency of 13300 cd m^-2, 4.3 cd A^-1, 2.9 lm W^-1, and 1.8%, respectively.
