Learning from a Mineral Structure toward an Ultra‐Narrow‐Band Blue‐Emitting Silicate Phosphor RbNa₃(Li₃SiO₄)₄:Eu²⁺

Learning from natural mineral structures is an efficient way to develop potential host lattices for applications in phosphor converted (pc)LEDs. A narrow-band blue-emitting silicate phosphor, RbNa₃ (Li₃ SiO₄ )₄ :Eu²⁺ (RNLSO:Eu²⁺ ), was derived from the UCr₄ C₄ -type mineral model. The broad excitation spectrum (320-440 nm) indicates this phosphor can be well matched with the near ultraviolet (n-UV) LED chip. Owing to the UCr₄ C₄ -type highly condensed and rigid framework, RNLSO:Eu²⁺ exhibits an extremely small Stokes shift and an unprecedented ultra-narrow (full-width at half-maximum, FWHM=22.4 nm) blue emission band (λ_em =471 nm) as well as excellent thermal stability (96 %@150 °C of the initial integrated intensity at 25 °C). The color gamut of the as-fabricated (pc)LEDs is 75 % NTSC for the application in liquid crystal displays from the prototype design of an n-UV LED chip and the narrow-band RNLSO:Eu²⁺ (blue), β-SiAlON:Eu²⁺ (green), and K₂ SiF₆ :Mn⁴⁺ (red) components as RGB emitters.