Luminescence investigation and thermal stability study of Eu~(2+) and Eu~(2+)-Mn~(2+) codoped (Ba,Sr)Mg_2Al_6Si_9O_(30) phosphor

摘要

Eu~(2+) and Eu~(2+)-Mn~(2+) codoped (Ba,Sr)Mg_2Al_6Si_9O_(30) phosphors have been synthesized by solid state reaction, and their luminescent properties are investigated. Under the excitation of 330 nm, it is observed that the emission of Eu~(2+) consists of two emission bands, located at around 370 and 450 nm, which are attributed to two Eu~(2+) centers (Eu~(2+)(I) and Eu~(2+)(II)) ions substituting for two different Ba~(2+) and Mg~(2+) sites, respectively. As Sr~(2+) gradually substitutes Ba~(2+), the emission bands of Eu~(2+)(I) shift to longer wavelength whereas the emission bands of Eu~(2+)(H) exhibit no change. This phenomenon is discussed in terms of the crystal-field strength. A detail analysis on the energy transfer from Eu~(2+) to Ma~(2+) in SrMg_2Al_6Si_9O_(30) host is presented, which indicates the energy of the red emission of Mn~(2+) is derived mainly from Eu~(2+)(I). We have also demonstrated that BaMg_2Al_6Si_9O_(30): Eu~(2+), Mn~(2+) exhibits better thermal quenching properties than that of SrMg_2Al_6Si_9O_(30):Eu~(2+), Mn~(2+) because of bigger activation energy.