For the purpose of development of highly energy-efficient light sources,one needs to design highly efficient green,red and yellow phosphors,which are able to absorb excitation energy and generate emissions.In this con...For the purpose of development of highly energy-efficient light sources,one needs to design highly efficient green,red and yellow phosphors,which are able to absorb excitation energy and generate emissions.In this contribution,we present our results on producing some efficient phosphors with improved luminescence properties.Using double activation,energy could be transferred from one luminescent activator to the other one,resulting in more efficient or brighter device operation.Co-activators could be added to a host material to change the color of the emitted light.The incorporation of Eu3+ or Tb3+ ions into the CaWO4 crystal lattice modified the luminescence spectrum due to the formation of the emission centers that generated the specific red and green light.Very efficient new red phosphors based on YNbO4 and doped by Eu3+,Ga3+,Al3+ allowed recommending these materials as good candidates for different applications including LED and X-ray intensifying screens.For double activated TAG with Ce3+ and Eu3+ and for different mole ratios of Ce/Eu,the color temperature changed from 5500 K(0.331,0.322) up to 4200 K(0.370,0.381) and the light became 'warmer'.Application of TAG:Ce,Eu in the light emitting device showed better chromaticity coordinates of luminescence and color rendering index of LEDs.展开更多
基金Project supported by the Korea Science and Engineering Foundation (KOSEF) through NRL (M10400000045-04J0000-04510)NCRC (R15-2008-006-00000-0)+1 种基金the Basic Research Program (R01-2005-000-10530-0)Ministry of Education,Science and Technology in Korea
文摘For the purpose of development of highly energy-efficient light sources,one needs to design highly efficient green,red and yellow phosphors,which are able to absorb excitation energy and generate emissions.In this contribution,we present our results on producing some efficient phosphors with improved luminescence properties.Using double activation,energy could be transferred from one luminescent activator to the other one,resulting in more efficient or brighter device operation.Co-activators could be added to a host material to change the color of the emitted light.The incorporation of Eu3+ or Tb3+ ions into the CaWO4 crystal lattice modified the luminescence spectrum due to the formation of the emission centers that generated the specific red and green light.Very efficient new red phosphors based on YNbO4 and doped by Eu3+,Ga3+,Al3+ allowed recommending these materials as good candidates for different applications including LED and X-ray intensifying screens.For double activated TAG with Ce3+ and Eu3+ and for different mole ratios of Ce/Eu,the color temperature changed from 5500 K(0.331,0.322) up to 4200 K(0.370,0.381) and the light became 'warmer'.Application of TAG:Ce,Eu in the light emitting device showed better chromaticity coordinates of luminescence and color rendering index of LEDs.
