Emerging ultra-narrow-band cyan-emitting phosphor for white LEDs with enhanced color rendition

Ming Zhao; Hongxu Liao; Maxim S Molokeev; Yayun Zhou; Qinyuan Zhang; Quanlin Liu; Zhiguo Xia

doi:10.1038/s41377-019-0148-8

Emerging ultra-narrow-band cyan-emitting phosphor for white LEDs with enhanced color rendition

Light Sci Appl. 2019 Apr 10:8:38. doi: 10.1038/s41377-019-0148-8. eCollection 2019.

Authors

Ming Zhao¹, Hongxu Liao¹, Maxim S Molokeev^{2

3

4}, Yayun Zhou⁵, Qinyuan Zhang⁵, Quanlin Liu¹, Zhiguo Xia^{1

5}

Affiliations

¹ 1The Beijing Municipal Key Laboratory of New Energy Materials and Technologies, School of Materials Sciences and Engineering, University of Science and Technology Beijing, 100083 Beijing, China.
² 2Laboratory of Crystal Physics, Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk,, 660036 Russia.
³ 3Siberian Federal University, Krasnoyarsk, 660041 Russia.
⁴ 4Department of Physics, Far Eastern State Transport University, Khabarovsk, 680021 Russia.
⁵ 5State Key Laboratory of Luminescent Materials and Devices and Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques, South China University of Technology, 510641 Guangzhou, China.

Abstract

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_0.5K_0.5Li₃SiO₄:Eu²⁺ (NKLSO:Eu²⁺) 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 UCr₄C₄-type compounds. NKLSO:Eu²⁺ 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.