期刊
CHEMISTRY-A EUROPEAN JOURNAL
卷 10, 期 19, 页码 4735-4741出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/chem.200400282
关键词
exchange interaction; laser spectroscopy; luminescence; upconversion
Yb3+-doped MnCl2 and MnBr2 crystals exhibit strong red upconversion luminescence under near-infrared excitation around 10 000 cm(-1) at temperatures below 100 K. The broad red luminescence band is centred around 15 200 cm(-1) for both compounds and identified as the (Mn2+T1g)-T-4-->(6)A(1g) transition. Excitation with 10 ns pulses indicates that the upconversion process consists of a sequence of ground-state and excited-state absorption steps. The experimental VIS/NIR photon ratio at 12 K for an excitation power of 191 mW focused on the sample with a 53 mm lens is 4.1% for MnCl2:Yb3+ and 1.2% for MnBr2:Yb3+. An upconversion mechanism based on exchange coupled Yb3+-Mn2+ ions is proposed. Similar upconversion properties have been reported for RbMnCl3:Yb3+, CsMnCl3:Yb3+, CsMnBr3:Yb3+, RbMnBr3:Yb3+, Rb2MnCl4:Yb3+. The efficiency of the upconversion process in these compounds is strongly dependent on the connectivity between the Yb3+ and Mn2+ ions. The VIS/NIR photon ratio decreases by three orders of magnitude along the series of corner-sharing Yb3+-Cl--Mn2+, edge-sharing Yb3+-(Cl-)(2)-Mn2+ to face-sharing Yb3+-(Br-)(3)-Mn2+ bridging geometry. This trend is discussed in terms of the dependence of the relevant super-exchange pathways on the Yb3+-Mn2+ bridging geometry.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据