Interconfigurational d-f luminescence of Pr3+ ions in praseodymium doped Li6Y(BO3)3 single crystals

• Luminescence properties of undoped Li6Y(BO3)3 (LYB) crystals grown by the Bridgman method as well as undoped and praseodymium doped LYB crystals grown by the Czochralski method were studied under excitation by ultraviolet light, synchrotron radiation and electron beam in the temperature region of 5–300 K. The emission bands peaking at 4.8, 3.76 and 2.95 eV were found in undoped Czochralski-grown crystals, while the band at 3.34 eV was dominant in the Bridgman-grown crystals. These bands are presumably ascribed to excitons localized at regular and defect-perturbed lattice sites. Intense emission bands peaking at 4.75, 4.50, 4.17 and 3.98 eV were discovered in Pr doped crystals at low temperatures and related to the interconfigurational 4f15d1 → 4f2 radiative transitions in Pr3+ ions. The structure of the emission spectrum is shown to be determined by the 3H4, 3H5, 3H6, 3F2, 3F3, 3F4 terms of the Pr3+ ion. The characteristic decay time of the 4f15d1 → 4f2 emission is τ = 24 ns at low temperatures, however, it shortens to 9 ns by room temperature due to a strong thermal quenching. The study of glow curves and spectra of thermostimulated luminescence in Li6Y(BO3)3:Pr crystal irradiated by 10-keV electron beam shows that Pr3+ ions do not participate in an electron-hole recombination process.

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

Fast luminescence

Lithium yttrium borate crystals

Pr 5d-4f emission

Synchrotron radiation

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