Abstracts 2002

Abstract of Publication No. 428

Christine Reinhard, Rafael Valiente and Hans U. Güdel
Exchange-Induced Upconversion in Rb2MnCl4:Yb3+
J. Phys. Chem. B 106, 10051-10057 (2002)      Full Text (PDF)      DOI-Link     

Abstract: Crystals of Yb3+ doped Rb2MnCl4 exhibit very intense yellow-orange Mn2+ 4T1g 6A1g upconversion luminescence under near-infrared 2F7/2 2F5/2 Yb3+ excitation around 1 mm at 15 K. Excitation with 10 ns pulses indicates that the upconversion process consists of a sequence of ground-state and excited-state absorption steps. The upconversion mechanism is cooperative, involving both Yb3+ and Mn2+ ions in the crystal, and we postulate an exchange mechanism between adjacent Yb3+ and Mn2+ ions to account for the unusually high efficiency of the process. The efficiency of the upconversion process is dependent on the nature of the Yb3+-Mn2+ connectivity. The upconversion in Rb2MnCl4:Yb3+, with a linear Yb3+-Cl-Mn2+ arrangement, is 3 orders of magnitude more efficient than in the Yb3+-(Br)3-Mn2+ arrangement of face-sharing octahedra in CsMnBr3:Yb3+.

Last modified: 13.12.11 by Gabriela Frei