Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7839647 | Journal of Luminescence | 2018 | 39 Pages |
Abstract
Spectroscopic evaluations of Dy3+/Eu3+/Sm3+ and Tb3+/Eu3+/Sm3+ doped zinc phosphate glasses, based on excitation and emission spectra, and emission decay measurements, are particularly focused on potential white light-emitting diodes applications. All the excitation wavelengths located in the 337-382â¯nm range, match with the emissions of AlGaN, GaN and InGaN LEDs. The Dy3+/Eu3+/Sm3+ doped zinc phosphate glass excited at 347â¯nm displays yellowish white tonality according with the xâ¯=â¯0.396 and yâ¯=â¯0.408 CIE1931 chromaticity coordinates and correlated color temperature (CCT) value of 3837â¯K, whereas under 362, 374 and 382â¯nm excitations, it displays reddish-orange tonality with CIE1931 chromaticity coordinates (and CCT values): xâ¯=â¯0.503 and yâ¯=â¯0.398 (2075â¯K), xâ¯=â¯0.570 and yâ¯=â¯0.388 (1640 K), and xâ¯=â¯0.527 and yâ¯=â¯0.386 (1804 K), respectively, with color purities higher than 72%. The Dy3+ and Sm3+ emission decay analysis suggests that non-radiative energy transfer processes from Dy3+ to Eu3+ and/or Sm3+ and Sm3+ to Eu3+ take place with efficiencies of 0.09â¯Â±â¯0.04 and 0.15â¯Â±â¯0.04, respectively. The Dy3+ and Sm3+ emission decay fitting by the Inokuti-Hirayama model, indicates that electric dipole-quadrupole and quadrupole-quadrupole interactions might respectively mediate the energy transfer processes inside the Dy3+-Sm3+-Eu3+ clusters. The Tb3+/Eu3+/Sm3+ doped zinc phosphate glasses only exhibits reddish-orange emission tonality with CIE1931 chromaticity coordinates and (CCT values): xâ¯=â¯0.510 and yâ¯=â¯0.425 (2210â¯K), xâ¯=â¯0.549 and yâ¯=â¯0.399 (1754 K), xâ¯=â¯0.510 and yâ¯=â¯0.411 (2108â¯K), and xâ¯=â¯0.544 and yâ¯=â¯0.385 (1710 K), under 337, 361, 374 and 380â¯nm excitations, respectively, with color purities higher than 79% in all cases. The Tb3+ and Sm3+ emission decay shortening in presence of Sm3+ and Eu3+, and Tb3+ and Eu3+, respectively, points out Tb3+â Eu3+ and/or Sm3+ and Sm3+ â Eu3+ non-radiative energy transfers, with efficiencies of 0.08â¯Â±â¯0.04 and 0.04â¯Â±â¯0.05, respectively. The Inokuti-Hirayama model suggests that the Tb3+â Eu3+ and/or Sm3+ and Sm3+ â Eu3+ energy transfer processes might be, respectively, dominated by electric dipole-quadrupole and quadrupole-quadrupole interactions inside Tb3+-Sm3+-Eu3+ clusters.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
A.N. Meza-Rocha, S. Bordignon, A. Speghini, R. Lozada-Morales, U. Caldiño,