Energy Transfer and Up-Conversion in the Erbium Elpasolites Cs2NaErxY1-xCl6
M. Campbell and C.D. Flint
Laser Laboratory, Department of Chemistry, Birkbeck College, University of London, 29 Gordon Square, London, WC1H 0PP, U.K.
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The luminescence decay curves from the 4F9/2 and 4I9/2 states of the cubic hexachloroelpasolite crystals Cs2NaErxY1-xCl6 (x = 0.001รท1) have been measured over the temperature range 10-300 K. The 4I9/2 state undergoes an electric dipole vibronic-electric dipole vibronic cross-relaxation process at 300 K, but this mechanism is inefficient below 165 K. Excitation into the 4F9/2 state, results in emission in the green, blue and ultra violet regions. The up-conversion processes which could account for the ultraviolet emission are discussed.
DOI: 10.12693/APhysPolA.90.151
PACS numbers: 13.40.Hq, 31.70.Hq, 34.30.+h, 61.72.Ss, 78.55.Hx