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 337-382 nm range, match with the emissions of AlGaN, GaN and InGaN LEDs. The Dy3+/Eu3+/Sm3+ doped zinc phosphate glass excited at 347 nm displays yellowish white tonality according with the x = 0.396 and y = 0.408 CIE1931 chromaticity coordinates and correlated color temperature (CCT) value of 3837 K, whereas under 362, 374 and 382 nm excitations, it displays reddish-orange tonality with CIE1931 chromaticity coordinates (and CCT values): x = 0.503 and y = 0.398 (2075 K), x = 0.570 and y = 0.388 (1640 K), and x = 0.527 and y = 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 0.09 +/- 0.04 and 0.15 +/- 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): x = 0.510 and y = 0.425 (2210 K), x = 0.549 and y = 0.399 (1754 K), x = 0.510 and y = 0.411 (2108 K), and x = 0.544 and y = 0.385 (1710 K), under 337, 361, 374 and 380 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+ -> Eu3+ and/or Sm3+ and Sm3+ -> Eu3+ non-radiative energy transfers, with efficiencies of 0.08 +/- 0.04 and 0.04 +/- 0.05, respectively. The Inokuti-Hirayama model suggests that the Tb3+ -> Eu3+ and/or Sm3+ and Sm3+ -> Eu3+ energy transfer processes might be, respectively, dominated by electric dipole-quadrupole and quadrupole-quadrupole interactions inside Tb3+-Sm3+-Eu3+ clusters.

Zinc phosphate glasses activated with Dy 3+ /Eu 3+ /Sm 3+ and Tb 3+ /Eu 3+ /Sm 3+ for reddish-orange and yellowish white phosphor applications

Bordignon, S.;Speghini, A.;
2018-01-01

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 337-382 nm range, match with the emissions of AlGaN, GaN and InGaN LEDs. The Dy3+/Eu3+/Sm3+ doped zinc phosphate glass excited at 347 nm displays yellowish white tonality according with the x = 0.396 and y = 0.408 CIE1931 chromaticity coordinates and correlated color temperature (CCT) value of 3837 K, whereas under 362, 374 and 382 nm excitations, it displays reddish-orange tonality with CIE1931 chromaticity coordinates (and CCT values): x = 0.503 and y = 0.398 (2075 K), x = 0.570 and y = 0.388 (1640 K), and x = 0.527 and y = 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 0.09 +/- 0.04 and 0.15 +/- 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): x = 0.510 and y = 0.425 (2210 K), x = 0.549 and y = 0.399 (1754 K), x = 0.510 and y = 0.411 (2108 K), and x = 0.544 and y = 0.385 (1710 K), under 337, 361, 374 and 380 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+ -> Eu3+ and/or Sm3+ and Sm3+ -> Eu3+ non-radiative energy transfers, with efficiencies of 0.08 +/- 0.04 and 0.04 +/- 0.05, respectively. The Inokuti-Hirayama model suggests that the Tb3+ -> Eu3+ and/or Sm3+ and Sm3+ -> Eu3+ energy transfer processes might be, respectively, dominated by electric dipole-quadrupole and quadrupole-quadrupole interactions inside Tb3+-Sm3+-Eu3+ clusters.
2018
LIGHT-EMITTING-DIODES, ENERGY-TRANSFER, LUMINESCENCE PROPERTIES, TUNABLE LUMINESCENCE, GREENISH-YELLOW, DY3+, EU3+
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/991389
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 16
  • ???jsp.display-item.citation.isi??? 12
social impact