High thermal stability and red emitting phosphor Sr2LiAlO4: Sm3+ for white LED

Achieving high color rendering index (CRI) in white LEDs requires the use of red-emitting phosphors. With the expanding application range of high-power LEDs and laser diodes, the demand for thermal stability of phosphor has become increasingly stringent. In this study, a series of novel red-emitting phosphors Sr 2- x LiAlO 4 : x Sm 3+ ( x = 0.01–0.18) were synthesized by a solid-state reaction. Under 407 nm excitation, this phosphor displays a prominent red emission (608 nm) characterized by the dominant 4 G → 6 H transition of Sm 3+ . The phosphor maintains 98.5% of its luminescence intensity at 200°C compared to room temperature (30°C). This indicates that Sr 1.91 LiAlO 4 : 0.09Sm 3+ phosphor has excellent thermal stability, which is attributed to the high rigidity of its crystal structure. A white LED was fabricated by coating a 365 nm near-UV chip with a blend of phosphors: the red Sr 1.91 LiAlO 4 : 0.09Sm 3+ , a yellow-green (Sr, Ba) 2 SiO 4 : Eu 2+ and a blue BaMgAl 10 O 17 : Eu 2+ phosphors. The device emits white light with a high color rendering index (CRI) of 94.4 and a correlated color temperature (CCT) of 5625 K. The results demonstrate the promising application potential of the Sr 1.91 LiAlO 4 : 0.09Sm 3+ red phosphor in white LED applications.