Study on Spectra of La_2CaB_(10)O_(19): Eu~(3+) in VUV-VIS Range

摘要

Excitation and emission spectra of new borate La_2CaB_(10)O_(19) doped Eu~(3+) in VUV-VIS range, high resolution emission spectra at room temperature and lifetime of Eu~(3+) were investigated. The emission line at about 616 nm attributed to the ~5D_0 - ~7F_2 transition of Eu~(3+) is the most intense emission of Eu~(3+). The broad band at about 244 nm is originated from charge transition band (CTB) of O~(2-) -> Eu~(3+). According to the numbers of spectral lines ~5D_0 - ~7F_0 and ~5D_0 - ~7F_1 in high-resolution spectrum, Eu~(3+) ions occupy two crystallographic sites. The lifetimes of ~5D_0 - ~7F_0 transition of Eu~(3+) of two kinds of lattice sites are individually 2. 1 and 2.6 ms, and both are exponential decay. In the VUV excitation spectrum, complicated band between 130 and 170 nm consists of host absorption and f-d transition of Eu~(3+).