TY - JOUR
T1 - A green-yellow emitting oxyfluoride solid solution phosphor Sr 2Ba(AlO 4F) 1-x(SiO 5) x:Ce 3+ for thermally stable, high color rendition solid state white lighting
AU - Denault, Kristin A.
AU - George, Nathan C.
AU - Paden, Sara R.
AU - Brinkley, Stuart
AU - Mikhailovsky, Alexander A.
AU - Neuefeind, Jörg
AU - Denbaars, Steven P.
AU - Seshadri, Ram
PY - 2012/9/21
Y1 - 2012/9/21
N2 - A near-UV excited, oxyfluoride phosphor solid solution Sr 1.975Ce 0.025Ba(AlO 4F) 1-x(SiO 5) x has been developed for solid state white lighting applications. An examination of the host lattice, and the local structure around the Ce 3+ activator ions through a combination of density functional theory, synchrotron X-ray and neutron powder diffraction and total scattering, and electron paramagnetic resonance, points to how chemical substitutions play a crucial role in tuning the optical properties of the phosphor. The maximum emission wavelength can be tuned from green (λ em = 523 nm) to yellow (λ em = 552 nm) by tuning the composition, x. Photoluminescent quantum yield is determined to be 70 ± 5% for some of the examples in the series. Excellent thermal properties were found for the x = 0.5 sample, with the photoluminescence intensity at 160 °C only decreased to 82% of its room temperature value. Phosphor-converted LED devices fabricated using an InGaN LED (λ max = 400 nm) exhibit high color rendering white light with R a = 70 and a correlated color temperature near 7000 K. The value of R a could be raised to 90 by the addition of a red component, and the correlated color temperature lowered to near 4000 K.
AB - A near-UV excited, oxyfluoride phosphor solid solution Sr 1.975Ce 0.025Ba(AlO 4F) 1-x(SiO 5) x has been developed for solid state white lighting applications. An examination of the host lattice, and the local structure around the Ce 3+ activator ions through a combination of density functional theory, synchrotron X-ray and neutron powder diffraction and total scattering, and electron paramagnetic resonance, points to how chemical substitutions play a crucial role in tuning the optical properties of the phosphor. The maximum emission wavelength can be tuned from green (λ em = 523 nm) to yellow (λ em = 552 nm) by tuning the composition, x. Photoluminescent quantum yield is determined to be 70 ± 5% for some of the examples in the series. Excellent thermal properties were found for the x = 0.5 sample, with the photoluminescence intensity at 160 °C only decreased to 82% of its room temperature value. Phosphor-converted LED devices fabricated using an InGaN LED (λ max = 400 nm) exhibit high color rendering white light with R a = 70 and a correlated color temperature near 7000 K. The value of R a could be raised to 90 by the addition of a red component, and the correlated color temperature lowered to near 4000 K.
UR - http://www.scopus.com/inward/record.url?scp=84865029511&partnerID=8YFLogxK
U2 - 10.1039/c2jm33620k
DO - 10.1039/c2jm33620k
M3 - Article
AN - SCOPUS:84865029511
SN - 0959-9428
VL - 22
SP - 18204
EP - 18213
JO - Journal of Materials Chemistry
JF - Journal of Materials Chemistry
IS - 35
ER -