Green and red phosphor for LED backlight in wide color gamut LCD

Abstract

Wide color gamut (WCG) backlight for liquid crystal display (LCD) utilizing white light-emitting diodes (LED) has attracted considerable attention for their high efficiency and color reduction. In this review, recent developments in crystal structure, luminescence and applications of phosphors for wide color gamut LED backlight are introduced. As novel red phosphors, Mn4+ activate fluoride and aluminate phosphors are advanced in quantum efficiency, thermal quenching and color saturation for their characteristic spectrum with broad excitation band and linear emission. The crystal structure and fluorescence properties of Mn4+ doped fluosilicate, fluorogermanate, fluotitanate, as well as Sr4Al14O25, CaAl12O19 and BaMgAl10O17 phosphors are discussed in detail. A serial of narrow-band red-emitting Eu2+, Eu3+ and Pr3+-doped nitride silicates and molybdate phosphors are also introduced. Rare-earth-doped oxynitride and silicate green-emitting phosphors have attracted more and more attention because of the wide excitation, narrow emission, high quenching temperature, high quantum efficiency, such as β-sialon:Eu2+, Ba3Si6O12N2:Eu2+, MSi2O2N2:Eu2+ (M = Ca, Sr, Ba), γ-AlON:Mn2+ and Ca3Sc2Si3O12:Ce3+. All above phosphors demonstrate their adaptability in wide color gamut LCD display. Especially for Mn4+ doped fluosilicate red phosphor and β-sialon: Eu2+ green phosphor. To achieve an ultra-high color gamut in white LED backlight and against the OLED, innovative narrow-band-emission red and green phosphor materials with independent intellectual property rights are continuously pursed.