Orangish-yellow-emitting Ca3Si2O7:Eu2+ phosphor for application in blue-light based warm-white LEDs

Abstract

A Eu(2+)-activated Ca3Si2O7:Eu(2+) orangish-yellow-emitting phosphor with strong luminescence was synthesized and its crystal structure was determined on the basis of XRD profiles using synchrotron radiation. The crystal structure was refined by the Rietveld refinement method. The excitation and emission spectra of the Ca3Si2O7:Eu(2+) phosphor show broad excitation bands in the range of 240-550 nm and a broad yellow emission band centered at 603 nm, depending on the concentration of Eu(2+). The optimized concentration of Eu(2+) in the Ca3Si2O7:Eu(2+) phosphor was determined to be 0.015 mol. The critical distance and average decay time were found to be short and fast, respectively, ranging from 19.74 Å to 13.69 Å and from 2.56 μs to 2.34 μs on increasing the Eu(2+) doping content. Warm-white light-emitting diodes (LEDs) fabricated using an InGaN-based blue LED chip combined with the Ca3Si2O7:0.015Eu(2+) phosphor gave color rendering indices between 76.0 and 38.9, correlated color temperatures between 1924 K and 4992 K, and tuned CIE chromaticity coordinates in the range from orangish-yellow (0.543, 0.389) to reddish purple (0.333, 0.219). The color coordinates and emission intensity of a Ca3Si2O7:0.015Eu(2+)-based white LED display were slightly yellow-shifted and the intensity increased on increasing the forward-bias current. These results indicate that orangish-yellow-emitting Ca3Si2O7:0.015Eu(2+) can serve as a promising candidate for applications in warm-white LEDs.

Garnet-based Li6CaLa2Sb2O12:Eu3+red phosphors: a potential color-converting material for warm white light-emitting diodes

“…6,7 To solve this issue, it is essential to introduce red phosphors into the traditional color conversion layer. 6,7 To solve this issue, it is essential to introduce red phosphors into the traditional color conversion layer.…”

“…16 Digital images and CIE chromaticity diagram of WLED devices fabricated by coupling an InGaN blue chip with the 3 wt% YAG:Ce 3+ and(1,3,5,7,9,15) wt% LCLSO:Eu 3+ co-doped GC. 16 Digital images and CIE chromaticity diagram of WLED devices fabricated by coupling an InGaN blue chip with the 3 wt% YAG:Ce 3+ and(1,3,5,7,9,15) wt% LCLSO:Eu 3+ co-doped GC.…”

VUV/Vis Photoluminescence, Site Occupancy, and Thermal‐Resistance Properties of K4SrSi3O9:Ce3+

“…Silicate materials have many unique properties (remarkable thermal/chemical stability) originating from their rigid structural frameworks with covalent Si−O bonds . Hence, silicates are widely used as hosts for doping with lanthanide ions to obtain excellent phosphors in the field of solid‐state lighting, for example, Ca 3 Sc 2 Si 3 O 12 :Eu 2+ , Ca 3 Si 2 O 7 :Eu 2+ , and LiY 9 (SiO 4 ) 6 O 2 :Ce 3+ …”

“…[4] Silicate materials have many unique properties (remarkable thermal/ chemicals tability) originating from their rigid structuralf rameworks with covalentS i ÀOb onds. [5] Hence, silicates are widely used as hosts for doping with lanthanide ions to obtain excellent phosphors in the field of solid-statel ighting, for example, Ca 3 Sc 2 Si 3 O 12 :Eu 2 + , [6] Ca 3 Si 2 O 7 :Eu 2 + , [7] and LiY 9 (SiO 4 ) 6 O 2 :Ce 3 + . [8] Herein, we report the design and synthesiso fs ilicatep hosphor K 4 SrSi 3 O 9 :Ce 3 + by af acile high-temperature solid-state re-action and determination of its crystal structure and chemical composition by the Rietveld refinement method.…”

Facile synthesis and optical properties of Ce:YAG polycrystalline ceramics with different SiO2content

“…15 First, although YAG:Ce 3+ owns many advantages such as excellent chemical and thermal stability and a broad band emission in the visible spectral region 16,17 in practical applications, such a design will generate a cool white light with a high correlated color temperature (CCT) and poor color rendering index (CRI) due to the shortage of red-emitting component in the luminescent spectra. 18,19 Second, because of its poor thermal conductivity, the organic resin and silicone deteriorate easily and turn yellow due to the accumulated heat emitted from a high-power blue chip with its output power increases. This raises some issues in WLED, such as degradation of luminous efficiency (LE) and long-term reliability, chromaticity shi, and reduction of lifetime.…”