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作 者:董宁[1] 陈彪[2] 郭海[3] 尹民[1] 张慰萍[3] 张其锦[2]
机构地区:[1]中国科学技术大学结构分析重点实验室 [2]中国科学技术大学高分子科学与工程系,安徽合肥230026 [3]中国科学技术大学物理系
出 处:《发光学报》2005年第5期659-663,共5页Chinese Journal of Luminescence
基 金:教育部跨世纪优秀人才计划;教育部博士点基金(20010358016)资助项目
摘 要:分别使用phen(1,10-邻菲咯啉)、TOPO(三正辛基氧化磷)、TPPO(三苯基氧化磷)作为第二配体与Sm(DBM)3(DBM:二苯甲酰甲烷)相互作用,合成了相应的配合物,然后分别将其掺入MMA中,进行聚合得到了固体样品。测量了不同第二配体样品及无第二配体样品的激发和发射光谱,对谱峰做了指认。发射谱中主要发射峰均为Sm3+的特征发射,有机配体的发光带很弱,说明从有机配体到稀土发光中心的能量传递非常有效。监测Sm3+离子644 nm发射峰(4G5/2→6H9/2)测量了样品的激发光谱。结果显示,第二配体的加入改变了有机配体的能级结构,激发边出现明显的移动,同时紫外区的激发效率发生了变化,对发光产生了显著的影响。还测量了上述样品中Sm3+的4G5/2能级的发光衰减曲线,拟合出该能级的跃迁寿命,针对不同第二配体的情况进行了比较分析。实验结果表明,第二配体的共轭性和化学键匹配对发光强度影响很大,在我们的结果中,第二配体为TPPO时发光效率最高。Rare earth organic chelate materials attract wide interest for its particular intense emission of rare earth ions compared to the rare earth doped inorganic materials. This is achieved by the organic ligands for its strong absorption in ultraviolet region and efficient energy transfer to the rare earth ion centers. It leads to lots of applications in the fields of electroluminescence, waveguide devices and fiber amplifiers. During the studies, secondary ligand is found to be of much importance. It can substitute water chelate to reduce the non-radiative relaxation, take part in the energy transfer process, and absorb photons to affect the absorption limits. The synthesis and luminescent properties of Sm (DBM)3 doped PMMA (polymethyl methacrylate) with three different secondary ligands : phen, TOPO, TPPO ( DBM : dibenzoyl methane, Phen : 1,10-phenanthroline, TOPO: trioctylphophine oxide, TPPO: triphenylphophine oxide) are reported. The emission and excitation spectra of samples with and without secondary ligand are recorded. The emission peaks are assigned to different transitions of Sm^3+ , as a weak broad band also appears due to direct emission from ligands. The excitation bands of different secondary ligands show obvious shifts compared to that of pure Sm (DBM) 3 doped PMMA, the excitation efficiency also varies. Decay curves of the Sm^3+ emission of all these samples are measured, and lifetimes of the level 4 G5/2 are obtained. The spectroscopic differences among the samples are discussed. The results show that the best secondary ligand here is TPPO.
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