Discovery of a novel rare-earth free narrow-band blue-emitting phosphor Y3Al2Ga3O12:Bi3+ with strong NUV excitation for LCD LED backlights

Abstract

A narrow-band emitting phosphor is essential for high performance liquid crystal display (LCD) backlights. However, most of the narrow-band emitting phosphors are only realized by doping Eu or Mn ions, which limits the optional range. Especially, the discovery of narrow-band blue-emitting phosphors without resorption in the visible light region is still challenging. Herein, an emerging rare-earth free and narrow-band blue-emitting phosphor, Y₃Al₂Ga₃O₁₂:Bi³⁺, with high color purity (up to 90.9%) has been discovered via selective excitation for the first time. The luminescence properties such as photoluminescence (PL), photoluminescence excitation (PLE) and lifetime spectra were systematically investigated. The sample exhibited tunable emission ranging from red to green and then to blue under variable excitation, originating from four Bi luminescence centers. Y₃Al₂Ga₃O₁₂:Bi³⁺ exhibits a narrow-band blue emission centered at 410 nm with a full width at half maximum of 39 nm and strong absorption in the range of 260–380 nm, which matches well with the commercial near-ultraviolet (NUV) chip. What's more, the sample shows remarkable thermal stability, retaining 90.71% of its room temperature emission intensity at 420 K. In this work, a rare-earth free narrow-band blue-emitting phosphor has been discovered for the first time.