Ce4+离子在Ca2SnO4一维结构基质中的电荷迁移光谱研究

利用高温固相反应法制备了Ca₂Sn_1-xCe_xO₄和Ca_2-ySr_ySn_1-xCe_xO₄一维结构发光体. XPS结果显示 Ca₂SnO₄拥有两种结合能分别为5277 eV和5293 关键词： 2Sn_1-xCe_xO₄')" href="#">Ca₂Sn_1-xCe_xO₄ 2-ySr_ySn_1-xCe_xO₄')" href="#">Ca_2-ySr_ySn_1-xCe_xO₄ 一维结构 电荷迁移光谱

Investigation of the charge-transfer spectra of Ce4+-doped Ca2SnO4 with one-dimensional structure

Ca₂Sn_1-xCe_xO₄ and Ca_2-ySr_ySn_1-xCe_xO₄ with one-dimensional structures were prepared by the solid-state reaction method. The X-ray photoelectron spectra of Ce⁴⁺-doped Ca₂SnO₄ showed the existence of two oxidation states of O^2- ions with binding energy peaks at 5277 eV and 5293 eV. The former corresponds to the terminal O^2- ions in the SnO₆ octahedra while the latter corresponds to the equatorial O^2- ions of the octahedra. The luminescence from Sr₂CeO₄ and Ca₂Sn_1-xCe_xO₄ phosphors with one-dimensional structures originates from a ligand-to-metal Ce⁴⁺ charge transfer (CT) and it is generally accepted that there exist two excitation peaks in the ultraviolet excitation band. However, it was found from the Ca_2-ySr_ySn_1-xCe_xO₄ sample that the excitation band of Ca₂Sn_1-xCe_xO₄ was actually comprised of three excitation peaks which were centered at about 31000, 34500 and 37400cm^-1. When Sr²⁺ ions were doped in Ca₂Sn_1-xCe_xO₄, three excitation components peaking at about 31200, 34700 and 38400cm^-1 were observed apparently, whose locations exhibited a blue shift as compared with those of Ca₂Sn_1-xCe_xO₄. However, the substitution of Ca²⁺ by Sr²⁺ had no influence on the shape of the emission spectrum. The excitation spectrum of Sr₂CeO₄ can also be deconvoluted into three Gassian components which are centered at about 29300, 33400 and 37000cm^-1, respectively.