The discovery of high efficiency narrow-band green-emitting phosphors is a major challenge in backlighting light-emitting diodes (LEDs). Benefitting from highly condensed and rigid framework structure of UCr C -type compounds, a next-generation narrow green emitter, RbLi(Li SiO ) :Eu (RLSO:Eu ), has emerged in the oxide-based family with superior luminescence properties. RLSO:Eu phosphor can be efficiently excited by GaN-based blue LEDs, and shows green emission at 530 nm with a narrow full width at half maximum of 42 nm, and very low thermal quenching (103%@150 °C of the integrated emission intensity at 20 °C), however its chemical stability needs to be improved later. The white LED backlight using optimized RLSO:8%Eu phosphor demonstrates a high luminous efficacy of 97.28 lm W and a wide color gamut (107% National Television System Committee standard (NTSC) in Commission Internationale de L'Eclairage (CIE) 1931 color space), suggesting its great potential for industrial applications as liquid crystal display (LCD) backlighting.
Phosphor-converted white LEDs rely on combining a blue-emitting InGaN chip with yellow and red-emitting luminescent materials. The discovery of cyan-emitting (470–500 nm) phosphors is a challenge to compensate for the spectral gap and produce full-spectrum white light. Na
0.5
K
0.5
Li
3
SiO
4
:Eu
2+
(NKLSO:Eu
2+
) phosphor was developed with impressive properties, providing cyan emission at 486 nm with a narrow full width at half maximum (FWHM) of only 20.7 nm, and good thermal stability with an integrated emission loss of only 7% at 150 °C. The ultra-narrow-band cyan emission results from the high-symmetry cation sites, leading to almost ideal cubic coordination for UCr
4
C
4
-type compounds. NKLSO:Eu
2+
phosphor allows the valley between the blue and yellow emission peaks in the white LED device to be filled, and the color-rendering index can be enhanced from 86 to 95.2, suggesting great applications in full-spectrum white LEDs.
A robust and stable narrow-band green emitter is recognized as a key enabler for wide-color-gamut liquid crystal display (LCD) backlights. Herein, an emerging rare earth silicate phosphor, RbNa(Li 3 SiO 4 ) 2 :Eu 2+ (RN:Eu 2+ ) with exceptional optical properties and excellent thermal stability, is reported. The resulting RN:Eu 2+ phosphor presents a narrow green emission band centered at 523 nm with a full width at half maximum of 41 nm and excellent thermal stability (102%@425 K of the integrated emission intensity at 300 K). RN:Eu 2+ also shows a high quantum efficiency, an improved chemical stability, and a reduced Stokes shift owing to the modified local environment, in which [NaO 8 ] cubes replace [LiO 4 ] squares in RbLi(Li 3 SiO 4 ) 2 :Eu 2+ via polyhedron transformation. White light-emitting diode (wLED) devices with a wide color gamut (113% National Television System Committee (NTSC)) and high luminous efficacy (111.08 lm W −1 ) are obtained by combining RN:Eu 2+ as the green emitter, K 2 SiF 6 :Mn 4+ as the red emitter, and blue-emitting InGaN chips. Using these wLEDs as backlights, a prototype 20.5 in. LCD screen is fabricated, demonstrating the bright future of stable RN:Eu 2+ for wide-colorgamut LCD backlight application.
Learning from natural mineral structures is an efficient way to develop potential host lattices for applications in phosphor converted (pc)LEDs. A narrow-band blue-emitting silicate phosphor, RbNa (Li SiO ) :Eu (RNLSO:Eu ), was derived from the UCr C -type mineral model. The broad excitation spectrum (320-440 nm) indicates this phosphor can be well matched with the near ultraviolet (n-UV) LED chip. Owing to the UCr C -type highly condensed and rigid framework, RNLSO:Eu exhibits an extremely small Stokes shift and an unprecedented ultra-narrow (full-width at half-maximum, FWHM=22.4 nm) blue emission band (λ =471 nm) as well as excellent thermal stability (96 %@150 °C of the initial integrated intensity at 25 °C). The color gamut of the as-fabricated (pc)LEDs is 75 % NTSC for the application in liquid crystal displays from the prototype design of an n-UV LED chip and the narrow-band RNLSO:Eu (blue), β-SiAlON:Eu (green), and K SiF :Mn (red) components as RGB emitters.
Learning from natural mineral structures is an efficient way to develop potential host lattices for applications in phosphor converted (pc)LEDs. A narrow‐band blue‐emitting silicate phosphor, RbNa3(Li3SiO4)4:Eu2+ (RNLSO:Eu2+), was derived from the UCr4C4‐type mineral model. The broad excitation spectrum (320–440 nm) indicates this phosphor can be well matched with the near ultraviolet (n‐UV) LED chip. Owing to the UCr4C4‐type highly condensed and rigid framework, RNLSO:Eu2+ exhibits an extremely small Stokes shift and an unprecedented ultra‐narrow (full‐width at half‐maximum, FWHM=22.4 nm) blue emission band (λem=471 nm) as well as excellent thermal stability (96 %@150 °C of the initial integrated intensity at 25 °C). The color gamut of the as‐fabricated (pc)LEDs is 75 % NTSC for the application in liquid crystal displays from the prototype design of an n‐UV LED chip and the narrow‐band RNLSO:Eu2+ (blue), β‐SiAlON:Eu2+ (green), and K2SiF6:Mn4+ (red) components as RGB emitters.
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