Loading...
Intense Green/Yellow Dual-Chromatic Calcium Chlorosilicate Phosphor Ca3SiO4Cl2:Eu2+–Mn2+ for Yellow and White LED, An
Ding, Weijia Wang, Jing Liu, Zongmiao Zhang, Mei Su, Qiang Tang, Jinke
Ding, Weijia
Wang, Jing
Liu, Zongmiao
Zhang, Mei
Su, Qiang
Tang, Jinke
Abstract
Description
A series of intense green/yellow phosphors Ca3SiO4Cl2:Eu2+,Mn2+ was synthesized by a high-temperature solid-state reaction. Their luminescent properties were characterized by means of powder diffuse reflection, photoluminescence excitation and emission spectra, and lifetime and temperature-dependent emission spectra in the temperature range of 10–450 K. The phosphors Ca3SiO4Cl2:Eu2+,Mn2+ show intense broad absorption bands between 250 and 450 nm, matching well with the near-ultraviolet 380–420 nm emission band of InGaN-based chips, and exhibit two dominating bands situated at 512 and 570 nm, ascribed to the allowed 5d → 4f transition of the Eu2+ ion and the 4T1g 4G → 6A1g 6S transition of the Mn2+ ion, respectively. The lifetime of the Eu2+ ion decreases with increasing the concentration of the Mn2+ ion, strongly supporting an efficient energy transfer from Eu2+ to Mn2+. By combining with near-ultraviolet 395 nm InGaN chips, intense yellow light-emitting diodes LEDs with a much lower ultraviolet light leakage were successfully fabricated based on the Ca3SiO4Cl2:Eu2+,Mn2+ phosphor, and intense white LEDs were made based on a blend of blue chlorophosphate phosphor and the green/yellow phosphor Ca3SiO4Cl2:Eu2+,Mn2+. The color coordinate, correlated color temperature Tc, general color-rendering index Ra, and luminous efficiency of the fabricated white LEDs are 0.3281, 0.3071, 6065 K, 84.5, and 11 lm/W, respectively.
Date
2008-03-17
Journal Title
Journal ISSN
Volume Title
Publisher
University of Wyoming. Libraries
Research Projects
Organizational Units
Journal Issue
Keywords
Physical Sciences and Mathematics