搜索

x
中国物理学会期刊

Sr2CeO4电荷迁移发光的光谱结构规律研究

CSTR: 32037.14.aps.54.2369

Investigation of the spectra of Sr2CeO4 due to charge transfer transition

CSTR: 32037.14.aps.54.2369
PDF
导出引用
  • 利用高温固相反应法分别合成了不同物相形成机理的Sr2CeO4,Sr 2CeO4∶Ca 2+和Sr2CeO4∶Ba2+样品,并对其光谱特性进行 了研究.结果发现,对于由SrO和CeO2直接反应生成的Sr2CeO4(Ⅰ),激发主峰位于256nm 左右;而对于SrCeO3和SrO反应生成的Sr2CeO4(Ⅱ),激发主峰位于279nm左右.在Sr2CeO4(Ⅰ)中掺入Ca2+,其激发光谱随着Ca2+离子浓度的增加逐渐接近于Sr2CeO4(Ⅱ)的激发光谱.激发主峰带应属于CeO6八面体终端Ce4+—O2-键的电荷迁移 带.对于激发光谱中340nm左右的弱激发峰,其峰值波长不受形成机理及Ca2+掺杂的影响,只是其强度 随着 激发主峰的红移而增加,它可能属于CeO6八面体平面上Ce4+—O2-键的电荷 迁移带.形成机理及Ca2+掺杂对发射光谱没有影响.Ca2+在Sr 2CeO 4(Ⅱ)与Ba2+在Sr2CeO4(Ⅰ)和(Ⅱ)中均难 于替代Sr2+的位置.

     

    Sr2CeO4 and Ca2+/Ba2+ doped Sr2 CeO4 samples with two different formation mechanisms were prepared by a solid-state method and their luminescent properties were investigated. For the Sr2CeO4(Ⅰ) sam ples formed by the direct reaction between SrO and CeO2, the peak of the strong excitat ion band appeared at about 256 nm while that for the Sr2CeO4(Ⅱ) sa mples obtained by the reaction between SrCeO3 and SrO was observed at about 279nm. It w as found that the solubility of Ca2+ in Sr2CeO4(Ⅱ) w as very low while Ca2+ could replace part of Sr2+ in Sr2CeO 4(Ⅰ). The substitution of Sr2+ by Ca2+ in Sr2CeO4(Ⅰ) led to r ed shift of the strong excitation band and its spectral shape approached that of Sr2CeO4(Ⅱ) with the in crease of Ca2+. The strong excitation band was attributed to the char ge tr ansfer transition of the terminal Ce4+—O2- bonds of CeO6 octahedr a. The peak of the weak excitation band located at about 340nm remained unchange d in all the samples, however, its intensity was found to increase with red shif t of the strong excitation band. This band might originate from the charge trans fer transition of the equatorial Ce4+—O2- bonds of CeO6 octahedra . The formation mechanism and the doping of Ca2+ had no effect on the emission spectra. Ba2+ was not incorporated in the Sr2CeO 4 phase in any formation mechanism and it only produced a second crystalline phase of BaCeO3.

     

    目录

    /

    返回文章
    返回