Thermally stable novel double perovskite orange-red emitting Sr2InTaO6:Sm3+ phosphors with high CRI for WLEDs.

Novel double perovskite Sr 2 InTaO 6 :Sm3+ phosphors were synthesized by the high-temperature solid-state reaction. The phase purity, luminescent properties, and thermal stability were systematically investigated in this work. When monitoring the emission peak at 649 nm, Sr 2 InTaO 6 :Sm3+ phosphors present an absorption band due to the O2−→Sm3+ charge transfer. Under 407 nm excitation, Sr 2 InTaO 6 :5 mol%Sm3+ phosphor presents four emission peaks at 565, 603, 649, and 717 nm corresponding to the electron transition from 6G 5/2 level to 6H 5/2 , 6H 7/2 , 6H 9/2 and 6H 11/2 levels, respectively. The best doping concentration of Sr 2 InTaO 6 : x Sm3+ is optimized as x = 5 mol%. The chromaticity coordinates of Sr 2 InTaO 6 : x Sm3+ show high color stability and are located in the orange-red region. The residual luminescence intensity at 480 K reaches 86.64%, proving it has excellent thermal stability. Internal quantum efficiency (IQE) is measured as 67.1%. The prepared WLED (white light emitting diode) has a low correlation color temperature (CCT = 4853 K) and an excellent color rendering index (CRI, R a = 93) with CIE (Commission International de L′ Eclairage) coordinates (0.346, 0.349). Therefore, Sr 2 InTaO 6 :Sm3+ phosphors have excellent luminescent properties and promising application prospects. [ABSTRACT FROM AUTHOR]