中文摘要：

利用978 nm近红外光激发样品Ca F2∶Pb^2＋,Yb^3＋,在室温下观察到二价Pb^2＋离子在383 nm附近的紫外上转换发光。该发射峰对应于Pb^2＋离子的3P0＂1A1g（1S0）跃迁。瞬态光谱测量结果表明：在这个材料体系中,Pb^2＋离子的激发来自于Yb^3＋离子三聚体的合作敏化。但是随着Pb^2＋离子掺杂浓度的提高,Yb^3＋离子三聚体遭到结构性破坏,导致其合作发光减弱。本文首次利用Pb^2＋离子掺杂造成Yb^3＋离子三聚体的结构性破坏,从而引起合作荧光猝灭,并对在Ca F2基质中因其他二价离子的掺入而造成的Yb^3＋三聚体合作发光猝灭给予了合理的解释。

英文摘要：

At room temperature,the ultraviolet（ UV） upconversion emissions from Ca F2∶ Pb^2＋,Yb^3＋were observed under the excitation of 978 nm near infrared（ NIR） laser. The upconversion emission peak is centered at 383 nm,which is ascribed to the3P0＂1A1g（1S0） transition of Pb^2＋ions. Through the results of transient measurements,the upconversion process of Pb^2＋ions is confirmed. The energy transfer process is that three excited Yb^3＋ions simultaneously transfer their energy to one Pb^2＋ion. With the increasing of Pb^2＋concentration,the cooperative luminescence from Yb^3＋clusters decreases gradually. In order to explain this phenomenon,we propose a new cooperative luminescence quenching mechanism in this paper,which is originated from Pb^2＋induced structure destruction of Yb^3＋-trimers. The fluorescence quenching in Pb^2＋and Yb^3＋codoped Ca F2 is given a reasonable explanation.