Effects of Variation in Al Content on the Emission of Eu Doped CaAlSiN3 Red Phosphor Synthesized by Combustion Synthesis Method for White LEDs.

Shu-Chi Huang,Shyan‐Lung Chung

doi:10.3390/ijms222011301

Abstract

Effects of Al content on the formation and the photoluminescence properties of CaAlSiN3:Eu2+ phosphor (CASIN) were investigated by a combustion synthesis method. XRD (X-ray diffraction), combined with PL (photoluminescence), TEM-EDS (transmission electron microscope equipped with an energy-dispersive X-ray spectroscope), and SAED (selected area electron diffraction) measurements, show that the bar-like CASIN gives a stronger emission than the plate-like and agglomerated fine particles. The emission intensity increases as the Al content increased from Al = 0.2 to Al = 0.8, which resulted from the extent of formation of CASIN increases. Then, the emission intensity decreases as the Al content is increased from Al = 0.8 to Al = 1.5, which resulted from the transformation of morphology of CASIN and a large amount formation of AlN. In addition, the extent of formation of CASIN increases with increasing Al from Al = 0.2 to Al = 1.2 and begins to decrease as Al is further increased to 1.5, and thus the peak emission wavelength increases from 647 nm to 658 nm as the Al molar ratio is increased from 0.2 to 1.2 and begins to decrease when further increasing the Al molar ratio to 1.5, which resulted from the large amount of AlN formed.

Highlights

The white light-emitting diode (LED) has drawn much more attention because of high efficiency, long lifetime, compactness, environmental friendliness, and designable features
The XRD peak intensity of CaAlSiN3:Eu2+ phosphor (CASIN) increased with increasing Al to a maximum at Al = 1.2 but begins to decrease as Al is further increased to 1.5, indicating that the formation of CASIN continuously increases as Int
X-ray nanoprobe of national synchrotron radiation research center (NSRRC) to provide the obvious and direct proof to prove the relationship of particle’s morphology and emission intensity, as we describe in this article

Summary

Introduction

The white light-emitting diode (LED) has drawn much more attention because of high efficiency, long lifetime, compactness, environmental friendliness, and designable features. Besides the common requirements of high quantum efficiency, suitable emission colors and emission spectra, and high reliability, phosphors in the LED-based solid-state lighting are further required to have strong absorptions of ultraviolet or blue light and small thermal quenching. A new class of phosphors (i.e., rare-earth doped nitridosilicates) has been discovered and shown to be ideal for application in LED lighting due to their superior properties such as high quantum efficiency, red light emission, and high thermal and chemical stability [3]. CaAlSiN3:Eu2+ red-emitting phosphor materials have received great attention for excellent color rendition and thermal stability [4,5]. Articles discuss the relation of Al metal concentration in CaAlSiN3:Eu2+ red-emitting phosphor, i.e., X-ray diffraction intensity, photoluminescence intensity, and crystal’s morphology of Al metal concentration in CaAlSiN3:Eu2+ red-emitting phosphor

Methods

Results

Conclusion