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Ultraviolet emissions from Gd^3+ ions excited by energy transfer from pairs of photoexcited Er^3+ ions: upconversion luminescence from CsMgCl_3 crystals doped with Gd^3+ and Er3+

1994; Optica Publishing Group; Volume: 11; Issue: 5 Linguagem: Inglês

10.1364/josab.11.000913

1520-8540

Ali Gharavi, Gary L. McPherson,

Perovskite Materials and Applications

Crystals of CsMgCl3 containing Gd3+ and Er3+ exhibit UV emissions from excited Gd3+ ions when the 4S3/2(E) (546-nm) and the 2H11/2(F) (522-nm) states of Er3+ are pumped by pulsed laser excitation. The Gd3+ long-lived emissions that appear at 281 nm (τ = 6 ms) and 313 nm (τ = 3 ms) are assigned to the 6I7/2(C) and the 6P7/2(A) states, respectively. The luminescence dynamics indicate that the excited Gd3+ ions are produced by cooperative energy transfer from excited pairs of Er3+ ions. Direct excitation of the 4G9/2(T) state of Er3+ at 277 nm is shown to sensitize the Gd3+ emission at 281 nm. Excitation spectra that are observed when pumping the Er3+ states while monitoring the Gd3+ emissions indicate that there are spectroscopically distinct Er3+–Gd3+ clusters with slightly different absorption energies and noticeably different emission dynamics.