Highly Efficient and Thermally Stable Ba_0.75Al₁₁O_17.25: Eu²⁺, Mn²⁺ Phosphor with Dual Narrowband Blue and Green Emissions: A Promising Candidate for Wide Gamut Displays

Abstract

The discovery of Eu2+‐activated narrowband green phosphor is pivotal for wide gamut liquid crystal displays (LCDs) but facing a great challenge due to the broadband emitting nature of Eu2+ ions. Alternatively, Mn2+ ions can generate extremely narrow green emission band but suffering from their weak absorption. Herein, Eu2+ ions with strong absorption are used to sensitize Mn2+ ions in the Ba0.75Al11O17.25 host. The Mn2+ ions exhibit a green emission band peaked at 515 nm with an extremely narrow bandwidth of 27 nm. More importantly, the Eu2+ ions show strong absorption at 340–380 nm and a blue emission band peaked at 450 nm with a relatively narrow bandwidth of 51 nm. Thus, the Ba0.75Al11O17.25: Eu2+, Mn2+ phosphor can be used as a dual narrowband blue and green emitting phosphor with commercial ultraviolet diode chips excitation. Moreover, this phosphor exhibits impressive overall performance that fulfills the key standards of commercial phosphors, including high emission efficiency, excellent photoluminescence thermal stability, and outstanding chemical stability. The packaged light‐emitting diode (LED) using 365 nm chips, Ba0.75Al11O17.25: Eu2+, Mn2+ and K2TiF6:Mn4+ phosphor generates a ultrawide color gamut of 121% National Television Systems Committee (NTSC) in Commission Internationale de l'Eclairage 1931 (CIE 1931).

A highly Mn2+-doped narrowband green phosphor toward wide color-gamut display applications

“…Hexaaluminates are a class of hexagonal aluminate compounds that are frequently utilized as high-temperature catalysts, thermal barrier coatings, and phosphor hosts due to their unique layered structure and excellent physicochemical stability. [20][21][22] The structure of hexaaluminates consists of dense spinel blocks and mirror planes, stacked alternately along the c-axis. According to the difference in the charge and radius of the large cations positioned on the mirror planes, they can be classified as β-Al 2 O 3 and magnetoplumbite (PbFe 12 O 19 ) types.…”