Changes of fluorescent spectral features after successive rare earth doping of gadolinium oxide powders

Journal Article
Kityk, W. Kuznik, M.G. Brik, I. Cie´slik, A. Majchrowski, L. Jaroszewicz, N.S. AlZayed, A.M. El-Naggar, I. Sildos, S. Lange, V. Kiisk, I.V. . 2012
المجلة \ الصحيفة: 
Journal of Alloys and Compounds
رقم العدد: 
221– 225
مستخلص المنشور: 

We present a complex fluorescence study of a series of gadolinium oxide polycrystalline powders singly, doubly and triply doped with trivalent rare earth ions (Er3+, Tb3+, and Dy3+), to explore a possibility of their use as materials for white light emitting diodes. The excitation and luminescence spectra along with the decay kinetics were measured in the temperature range from 6 to 300 K. The luminescence efficiency was studied within the visible spectral range, i.e. −400 nm to 750 nm under excitation by 355 nm third harmonic Nd:YAG laser pulses. Singly doped Er3+ sample gave stronger luminescence signals, but others showed significantly larger decay lifetimes. The successive rare earths doping leads to substantial changes of the spectral positions due to the up-conversion processes. In the singly (Er3+) doped sample, following the time resolved spectrum and decay curves, there are two different types of emissions: at 660 nm and at shorter wavelengths (below 640 nm) the red emission’s lifetime is ten times longer than at shorter wavelengths. The singly doped sample shows unclear temperature-dependence of luminescence with lifetime at 550 nm (the longest at 100 K, similarly at 6 K and 300 K) and achieved luminous efficacy 73.5 lm/W.