Novel Na3Sc2(PO4)3:Ce3+, Tb3+ phosphors for white LEDs: Tunable blue-green color emission, high quantum efficiency and excellent thermal stability. (April 2018)

• Record Type: Journal Article
• Authors: Guo, Heng; Devakumar, Balaji; Li, Bin; Huang, Xiaoyong
• Is Part Of: Dyes and pigments. Volume 151(2018)
• Page Start: 81
• Page End: 88
• Publication Date: 2018-04
• Subjects: Rare-earth ions -- White LEDs -- Luminescence -- Ce3+ -- Tb3+ -- Energy transfer; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2017.12.051
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: In this paper, Ce 3+ and Tb 3+ singly doped as well as Ce 3+ /Tb 3+ co-doped Na3 Sc2 (PO4 )3 phosphors were synthesized by the traditional solid-state method and their crystal structure, morphology, luminescence properties, temperature-dependent emission spectra and quantum efficiency were investigated in detail. The Ce 3+ singly doped sample exhibited intense blue emission under 320 nm excitation. The Na3 Sc2 (PO4 )3 :Tb 3+ phosphors showed four emission bands in the wavelength range of 450–650 nm with a maximum at about 542 nm. Furthermore, efficient energy transfer from Ce 3+ to Tb 3+ ions occurred in Ce 3+ and Tb 3+ co-doped Na3 Sc2 (PO4 )3 phosphors, and the electric dipole-dipole interactions was responsible for the energy transfer mechanism. By adjusting Tb 3+ doping concentration in Na3 Sc2 (PO4 )3 :Ce 3+, Tb 3+ phosphors, their emission colours can be tuned appropriately from deep blue (0.171, 0.050) to green (0.299, 0.593), and the intensity of green emission reached the maximum at 10 mol% Tb 3+ . The Na3 Sc2 (PO4 )3 :0.03Ce 3+, 0.1Tb 3+ sample possessed high internal quantum efficiency of 65% and also excellent thermal stability with an activation energy of 0.245 eV. The relative emission intensity of Na3 Sc2 (PO4 )3 :0.03Ce 3+, 0.1Tb 3+ at 423 K was found to be about 85.6% of its initial value at 303 K. These results indicate the potential of Na3 Sc2 (PO4 )3 :Ce 3+, Tb 3+ compounds as candidates for color converters in phosphor-converted white light-emitting diodes. Graphical abstract: Highlights: Blue-green tunable emission was obtained in novel Na3 Sc2 (PO4 )3 :Ce 3+, Tb 3+ phosphors. Energy transfer from Ce 3+ to Tb 3+ occurred via electric dipole-dipole mechanism. Na3 Sc2 (PO4 )3 :Ce 3+, Tb 3+ possessed high internal quantum efficiency of 65%. The phosphors had excellent thermal stability with activation energy of 0.245 eV.