Title
Soluble silica assisted synthesis and luminescent characteristics of yellow emitting CaSrSiO4:Eu2+ phosphors for warm white light production
Author
Hyun-Joo Woo, Sakthivel Gandhi, Bong-Joon Kwon, Dong-Soo Shin, Seoung Soo Yi, Jung Hyun Jeong, Kiwan Jang
Year
2015
Journal
Ceramics International
Abstract
To meet the challenges and additional requirements towards the development of white LED׳s with utmost efficacy, a sol–gel approach is adopted wherein a water soluble silicon compound is used as a silica source. The phosphor material obtained is subjected to detailed structural, morphological and luminescent studies. The results obtained show that the XRD patterns of Eu2+ doped CaSrSiO4 phosphors are in good agreement with the CaSrSiO4 (ICSD no. 49660) whose structure is orthorhombic. The output of the luminescence studies clearly portrays a broad yellow emission between 450 and 750 nm with a peak at ~600 nm under the broad excitation range. This confirms its efficient emission towards the development of a warm white light using blue LEDs. A red shift in the peak emission wavelength was observed for the prepared samples. This longer shift in wavelength can be credited to the sol–gel method adopted and is not offered by the conventional solid state reaction method. A warm white emitting LED was fabricated by combining near ultraviolet LED (400 nm) chip with our sol–gel synthesized CaSrSiO4:Eu2+ phosphor. The CIE chromaticity coordinates (0.44 and 0.41), color correlated temperature (CCT) <4000 K, color rendering index (CRI) >80 provide their emission potentiality in the warm white light region.
Instrument
FP-8500
Keywords
Fluorescence, Photoluminescence, Optical properties, Thermal stability, Materials, LEDs