Abstracts 2004

Abstract of Publication No. 470

Christine Reinhard, Karl Krämer, Daniel A. Biner and Hans U. Güdel
Cooperative radiative and nonradiative effects in K2NaScF6 codoped with V3+ and Er3+
J. Chem. Phys. 120, 3374-3380 (2004)      Full Text (PDF)      DOI-Link     

Abstract: K2NaScF6 crystals codoped with V3+ and Er3+ exhibit some novel cooperative near-IR to visible upconversion processes at cryogenic temperatures. V3+ mainly acts as a broadband sensitizer. The V3+ 3T1g 3T2g excitation between 13 500 and 15 500 cm1, after fast relaxation to V3+ 1T2g, can be transferred to Er3+ 4I11/2, and then upconversion takes place. Four upconversion mechanisms are identified and characterized. For narrow-band laser excitation the overall efficiency of the upconversion processes is low. However, at 12 K for broadband excitation, such as in a lamp, between 12 000 and 14 500 cm1 the number of emitted visible photons is roughly doubled by codoping V3+ in addition to Er3+.

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