Facile synthesis of the desired red phosphor Li2Ca2Mg2Si2N6:Eu2+ for high CRI white LEDs and plant growth LED device

The red emission with suitable peak wavelength and narrow band is acutely required for high color rendering index (CRI) white LEDs without at the cost of the luminous efficacy. Herein, the Li 2 Ca 2 Mg 2 Si 2 N 6 :Eu 2+ red phosphor was prepared with facile solid-state method using Ca 3 N 2 , Mg 3 N 2 , Si 3 N 4 , Li 3 N, and Eu 2 O 3 as the safety raw materials under atmospheric pressure for the first time, which shows red emission peaking at 638 nm with full width at half maximum (FWHM) of 62 nm under blue light irradiation and becomes the desired red phosphor to realize the balance between luminous efficacy and high CRI in white LEDs. The morphology, structure, luminescence properties, thermal quenching behavior, and chromaticity stability of the Li 2 Ca 2 Mg 2 Si 2 N 6 :Eu 2+ phosphor are investigated in detail. Concentration quenching occurs when the Eu 2+ content exceeds 1.0 mol%, whereas high-temperature photoluminescent measurements show a 32% drop from the room-temperature efficiency at 423 K. In view of the excellent luminescence performances of Li 2 Ca 2 Mg 2 Si 2 N 6 :Eu 2+ phosphor, a white LEDs with CRI of 91 as a proof-of-concept experiment was fabricated by coating the title phosphor with Y 3 Al 5 O 12 :Ce 3+ on a blue LED chip. In addition, the potential application of the title phosphor in plant growth LED device was also demonstrated. All the results indicate that Li 2 Ca 2 Mg 2 Si 2 N 6 :Eu 2+ is a promising red-emitting phosphor for blue LED-based high CRI white LEDs and plant growth lighting sources.