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A novel red phosphor Cs2NaGaF6:Mn4+ with ultra-strong zero-phonon lines and long wavelength phonon sidebands for high-quality WLEDs.
- Source :
- Dalton Transactions: An International Journal of Inorganic Chemistry; 5/7/2023, Vol. 52 Issue 17, p5587-5596, 10p
- Publication Year :
- 2023
-
Abstract
- For high-efficiency lighting and wide color gamut backlight display, high-quality narrow-band red phosphors for WLEDs are still in high demand. Herein, a novel red-emitting fluoride phosphor Cs<subscript>2</subscript>NaGaF<subscript>6</subscript>:Mn<superscript>4+</superscript> was successfully synthesized by a simple two-step co-precipitation method and exhibits ultra-intense zero-phonon lines (ZPLs) and long wavelength phonon sidebands under 468 nm blue light irradiation. The ZPL emission peak of Cs<subscript>2</subscript>NaGaF<subscript>6</subscript>:Mn<superscript>4+</superscript> was located at 627 nm, which is much stronger than its υ<subscript>6</subscript> vibration peak, more matchable with the eye-sensitive region of humans, and beneficial for obtaining higher luminous efficiency of WLEDs. Interestingly, the υ<subscript>6</subscript> vibration peak of this red phosphor is at 636.5 nm, which is larger than that of the common fluoride phosphor A<subscript>2</subscript>BF<subscript>6</subscript>:Mn<superscript>4+</superscript> (usually at about 630 nm, represented by K<subscript>2</subscript>SiF<subscript>6</subscript>:Mn<superscript>4+</superscript>) at about 6.5 nm. Thanks to the longer wavelength of the υ<subscript>6</subscript> vibration peak, the chromaticity coordinates (0.7026, 0.2910) with a larger x-coordinate value were realized, leading to a potentially wider color gamut of WLEDs. In addition, this phosphor has high thermal stability and its emission intensity at 423 K remains 93.7% of the initial intensity at room temperature. The lumen efficiency of WLED1 packaged with a mixture of Cs<subscript>2</subscript>NaGaF<subscript>6</subscript>:Mn<superscript>4+</superscript> and YAG:Ce<superscript>3+</superscript> on the InGaN blue chip is 115.7 lm W<superscript>−1</superscript> with the color temperature (T<subscript>c</subscript>) = 3390 K and the colour rendering index (R<subscript>a</subscript>) = 92.5 under 20 mA driving current. The chromaticity coordinates of WLED2 packaged with Cs<subscript>2</subscript>NaGaF<subscript>6</subscript>:Mn<superscript>4+</superscript> and β-SiAlON:Eu<superscript>2+</superscript> on the InGaN blue chip are (0.3149, 0.3262) and the calculated color gamut is up to 118.4% (NTSC). These results indicate that Cs<subscript>2</subscript>NaGaF<subscript>6</subscript>:Mn<superscript>4+</superscript> red phosphors have promising applications in the high-quality lighting and display fields. [ABSTRACT FROM AUTHOR]
- Subjects :
- PHOSPHORS
PHONONS
COLOR temperature
WAVELENGTHS
BLUE light
TERBIUM
CESIUM compounds
Subjects
Details
- Language :
- English
- ISSN :
- 14779226
- Volume :
- 52
- Issue :
- 17
- Database :
- Complementary Index
- Journal :
- Dalton Transactions: An International Journal of Inorganic Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 163463563
- Full Text :
- https://doi.org/10.1039/d2dt03890k