Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1606938 | Journal of Alloys and Compounds | 2016 | 8 Pages |
Abstract
A blue-emitting Ca5(PO4)3Cl:Eu2+ phosphor was prepared via a conventional high temperature solid-state reaction method. Crystal and electronic structure properties of the Ca5(PO4)3Cl:Eu2+ phosphor were investigated using X-ray diffraction and density functional theory (DFT), respectively. The micro-morphology, reflectance spectra, thermal stability and quantum efficiency of the Ca5(PO4)3Cl:Eu2+ phosphor were also studied. The optimum Eu2+ concentration in Ca5(PO4)3Cl was determined to be 2.0 mol% and the concentration quenching mechanism can be explained by the dipole-dipole interaction. The emission intensity of the Ca5(PO4)3Cl:Eu2+ phosphor was 58.2% of the initial value when the measured temperature increased from 30 °C to 150 °C. The activation energy was determined to be 0.254 eV, suggesting the good stability of this phosphor. A bright blue LED was fabricated using an InGaN-based near-UV LED chip (385 nm) and a Ca5(PO4)3Cl:Eu2+ phosphor, and has an excellent blue-emitting property with CIE coordinates of (0.1480, 0.0350). Furthermore, a bright near-UV warm white LED was fabricated using an InGaN-based near-UV LED chip (395 nm) in combination with the present blue phosphor and the commercial green and red phosphors, which exhibits an excellent color-rendering index (Ra = 96.65) at a warm correlated color temperature of 3902 K with CIE coordinates of (0.3781, 0.3879). All the results suggest that the Ca5(PO4)3Cl:Eu2+ phosphor is a potential blue-emitting candidate for the application in the near-UV pumped blue and warm white LEDs.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Jianghui Zheng, Shunqing Wu, Guo Chen, Sijia Dang, Yixi Zhuang, Ziquan Guo, Yijun Lu, Qijin Cheng, Chao Chen,