Changes of fluorescent spectral features after successive rare earth doping of gadolinium oxide powders |
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Authors: | W. Kuznik M.G. BrikI. Cie?lik A. MajchrowskiL. Jaroszewicz N.S. AlZayedA.M. El-Naggar I. SildosS. Lange V. KiiskI.V. Kityk |
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Affiliation: | a Chemical Department, Silesian University of Technology, Gliwice, Poland b Institute of Physics, University of Tartu, Riia 142, Tartu 51014, Estonia c Institute of Applied Physics, Military University of Technology, Kaliskiego 2,00-908 Warsaw, Poland d Physics & Astronomy Dept., College of Science, P.O. Box 2455, King Saud University, Riyadh 11451, Saudi Arabia e Electrical Engineering Department, Czestochowa University of Technology, Armii Krajowej 17, Czestochowa, Poland f Permanent address: Physics department, Faculty of Science, Ain Shams University, Abassia, Cairo 11566, Egypt |
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Abstract: | 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. |
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Keywords: | Optical compounds Light emitting diodes Fluorescent spectra |
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