Closing the Cyan Gap Toward Full-Spectrum LED Lighting with NaMgBO₃:Ce³⁺

Abstract

The photoluminescence spectrum generated by an ordinary phosphor-converted white light-emitting diode (pc-wLED) that combines a blue LED chip with a yellow phosphor or a near-UV LED with red, green, and blue phosphors contains a notable cavity in the cyan region of the visible spectrum (480− 520 nm), which reduces the color quality produced by these lights. Here, we report a new bright blue-cyan-emitting phosphor, NaMgBO 3 :Ce 3+ , which bridges the gap. Rietveld refinements verify the rare-earth substitution while ab initio calculations prove that Ce 3+ occupies the Na + sites. NaMgBO 3 :Ce 3+ is excited by a broad range of near-UV light sources and produces a blue-cyan emission with a high (internal) quantum efficiency, minimal thermal degradation, and zero-chromaticity drift at elevated temperatures. Fabricating a near-UV (λ ex = 370 nm) pumped pc-wLED using NaMgBO 3 :Ce 3+ along with commercially available phosphors demonstrates a well-distributed warm white light with a high color-rendering index (R a ) of 91 and a low correlated color temperature (CCT) of 3645 K. Closing the cyan cavity with NaMgBO 3 :Ce 3+ is ideal for generating a pleasant, full-spectrum warm white light.

High-efficiency blue photoluminescence in the Cs2NaInCl6:Sb3+ double perovskite phosphor

“…To highlight the capability of Cs 2 NaInCl 6 :Sb 3+ as a blue-emitting phosphor a pc-LED with BaMgAl 10 O 17 :Eu 2+ , Sr 2 Si 5 N 8 :Eu 2+ and b-SiAlON:Eu 2+ was also fabricated. The luminescence spectrum and CIE coordinates of the pc-LED can be seen in Fig.S10 (ESI †) 23. The CIE coordinates of the BAM:Eu 2+ containing pc-LED closely resembles that of the pc-LED composed of Cs 2 NaInCl 6 :Sb 3+ , indicating a similar broad band spectrum can be produced from both blueemitters.…”

Enhanced Cyan Emission and Optical Tuning of Ca3Ga4O9:Bi3+ for High‐Quality Full‐Spectrum White Light‐Emitting Diodes

“…That is an obvious spectrum gap appearing in the cyan region (480–520 nm) of the visible spectrum, making it challenging to realize the full‐spectrum lighting that resembles sunlight. [ 6 ] To address this issue, an efficient cyan‐emitting phosphor is desired to close the cyan gap, which is indispensable to achieve high‐quality lighting with ultra‐high color rendering.…”

Near‐Unity Cyan‐Green Emitting Lead‐Free All‐Inorganic Cesium Copper Chloride Phosphors for Full‐Spectrum White Light‐Emitting Diodes

“…[ 7,8 ] However, it is still a great challenge to obtain full‐spectrum wLEDs with extra‐high color‐rendering properties due to the “cyan cavity” (a gap between blue and green emission in the 480–520 nm region), as shown in Figure S1, Supporting Information. [ 7,9 ] Hence, to develop cyan‐emitting phosphors is continuously pursued. [ 3,7,10 ] In addition, the use of multiple phosphors will result in the fabrication complexity and reabsorption.…”

“…[ 3 ] Therefore, it is a hotspot to design and discovery of new non‐rare‐earth‐ions‐activated cyan‐green emitting phosphors that can be facilely synthesized and have high PLQY as well as broadband emission. [ 2,5,9,15 ]…”