Luminescence enhancement of (Sr1-x Mx )2 SiO4 :Eu2+ phosphors with M (Ca2+ /Zn2+ ) partial substitution for white light-emitting diodes.
Eu2+ -doped Sr2 SiO4 phosphor with Ca2+ /Zn2+ substitution, (Sr1-x Mx )2 SiO4 :Eu2+ (M = Ca, Zn), was prepared using a high-temperature solid-state reaction method. The structure and luminescence properties of Ca2+ /Zn2+ partially substituted Sr2 SiO4 :Eu2+ phosphors were investigated in detail. With Ca2+ or Zn2+ added to the silicate host, the crystal phase could be transformed between the α-form and the β-form of the Sr2 SiO4 structure. Under UV excitation at 367 nm, all samples exhibit a broad band emission from 420 to 680 nm due to the 4f6 5d1  → 4f7 transition of Eu2+ ions. The broad emission band consists of two peaks at 482 and 547 nm, which correspond to Eu2+ ions occupying the ten-fold oxygen-coordinated Sr.(I) site and the nine-fold oxygen-coordinated Sr.(II) site, respectively. The luminescence properties, including the intensity and lifetime of Sr2 SiO4 :Eu2+ phosphors, improved remarkably on Ca2+ /Zn2+ addition, and promote its application in white light-emitting diodes. Copyright © 2016 John Wiley & Sons, Ltd.
['Wang|Yulong|Y|', 'Zhang|Wentao|W|', 'Gao|Yang|Y|', 'Long|Jianping|J|', 'Li|Junfeng|J|']
D002118:Calcium D005063:Europium D008027:Light D049449:Luminescence D017640:Silicates D013324:Strontium D015032:Zinc
solid-state reaction Sr2SiO4:Eu2+ cation substitution photoluminescence white LEDs