Structural Disorders in Gd2O2S:Tb Phosphors
The luminescence characteristics of Gd2O2S:Tb phosphors prepared under different conditions are described and the possibility of electroluminescence discussed. X-ray diffraction and cathodoluminescence results are used to optimise synthesis parameters. The analysis of diffraction data for reflection intensity distribution from different (hkl) plane shows the presence of a disordered crystal structure. Brightness of luminescence emission is found to depend upon the extent of this disorder. The green cathodoluminescence is primarily due to the characteristic line emission 5D4-7F4 of Tb3+ in the spectral region of 540 nm. Under ac field excitation, the voltage dependence of electroluminescnece (EL) brightness follows the Destriau relation, B = B0 exp (-b/Vl/2).
KeywordsRare Earth Brightness Wave Optimise Synthesis Parameter Yttrium Oxysulfide Disordered Crystal Structure
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- 5.C. Kittel: In Introduction to Solid State Phys., (Wiley & Sons, London 1971).Google Scholar