Line emission of SrBe2Si2O7:Eu2+ and BaBe2Si2O7:Eu2+
Line emission of SrBe2Si2O7:Eu2+ and BaBe2Si2O7:Eu2+
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DOI：
10.1016/0022-2313(74)90042-8
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发表时间：
1974-11
影响因子：
3.6
通讯作者：
J. Verstegen;J. L. Sommerdijk
中科院分区：
文献类型：
--
作者：
J. Verstegen;J. L. Sommerdijk
The compounds SrBe2Si2O7and BaBe2Si2O7both have the barylite structure. With 254 nm excitation, the Eu2+-activated compounds give UV emission peaking at 360 nm (Sr) and at 375 nm (Ba). Maximum quantum efficiencies of 40% (Sr) and 65% (Ba) were measured. The emission consists of a 5d-4f band emission as well as 4f-4f line emission, in contrast to many other Eu2+-activated oxides which generally show only 5d-4f band emission. At 77°K, both compounds show only the 4f-4f line emission peaking at 360 nm. At higher temperatures, 5d-4f band emission shows up at the cost of the line emission. A thermal equilibrium is assumed between the lowest excited 5d and 4f levels. The energy difference between these levels, calculated from the variation in the line-band intensity ratio with temperature, was computed to be 0.15 eV (Sr) and 0.09 eV (Ba). The occurrence of the line emission in the barylites is correlated with the weakness of the crystal field at the Eu2+ions and with the high quenching temperature of the 5d-4f band emission.
