Narrow-Band SrMgAl 10 O 17 :Eu 2+ , Mn 2+ Green Phosphors for Wide-Color-Gamut Backlight for LCD Displays.

The strength of the photoluminescence excitation (PLE) spectrum of SrMgAl ₁₀ O ₁₇ :Eu ²⁺ , Mn ²⁺ (SAM:Eu ²⁺ , Mn ²⁺ ) phosphor increased at deep blue (∼430 nm) and red-shifted from violet to deep blue with increasing concentrations of both Eu ²⁺ ions Mn ²⁺ ions. Eu ²⁺ -Mn ²⁺ energy transfer between Eu ²⁺ ions in Sr-O layer and Mn ²⁺ ions at Al-O tetrahedral sites was maximized, and the photoluminescence (PL) intensity of the narrow-band Mn ²⁺ emission was improved by optimizing the concentrations of Eu ²⁺ and Mn ²⁺ ions. The PL emission spectrum of the (Sr _0.6 Eu _0.4 )(Mg _0.4 Mn _0.6 )Al ₁₀ O ₁₇ (SAM:Eu ²⁺ , Mn ²⁺ ) phosphor peaks was optimized at 518 nm at a full width at half-maximum (FWHM) of 26 nm under light-emitting diode (LED) excitation at 432 nm LED. The color gamut area of a color-filtered RGB triangle of down-converted white LEDs (DC-WLEDs) incorporated with optimum SAM:Eu ²⁺ , Mn ²⁺ green and K ₂ SiF ₆ :Mn ⁴⁺ (KSF:Mn ⁴⁺ ) red phosphors is enlarged by 114% relative to that of the NTSC standard system in the CIE 1931 color space. The luminous efficacy of our DC-WLED was measured and found to be ∼92 lm/W at 20 mA. Increased energy transfers between dual activators and red-shifted band-edge and enhanced intensity of PLE spectrum indicate the possibility of developing dual-activated narrow-band green phosphors for wide-color gamut in an LCD backlighting system.
Competing Interests: The authors declare no competing financial interest.
(Copyright © 2020 American Chemical Society.)