Novel narrowband emitting red phosphor Sr ₃ La ₂ W ₂ O ₁₂ :Eu ³⁺ with excellent thermal stability for WLEDs

Abstract The development of red phosphors with good thermal stability, high quantum yield and high color purity is still a big challenge. In this work, a series of novel red phosphors Sr 3 La 2 W 2 O 12 : x Eu 3+ (0≤ x ≤0.18, ∆ x = 0.03) were successfully prepared by high‐temperature solid‐phase method. The phosphors reveal a hexagonal phase with the space group of R‐3 m. The phosphor Sr 3 La 2 W 2 O 12 :Eu 3+ produced narrowband red emission from 5 D 0 → 7 F 2 of Eu 3+ (616 nm) under excitation at 395 nm, 465 nm, and 533 nm. Importantly, phosphor Sr 3 La 2 W 2 O 12 :0.09Eu 3+ exhibits astonishing quantum efficiency (IQE = 89.60%, EQE = 41.52%), and it demonstrate robust thermal performance with the emission intensity retaining 92.73% at 558 K of that at 298 K. Finally, the prepared red phosphor Sr 3 La 2 W 2 O 12 :0.09Eu 3+ and yellow phosphor YAG:Ce 3+ were combined with a blue LED chip (460 nm) to form a WLED device, which presented warm white light with color coordinates of (0.3523, 0.3732), color rendering index of 83.7, and color temperature of 4826 K.