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

Novel double perovskite Sr2InTaO6:Sm3+ phosphors were synthesized by the high-temperature solid-state re-action. The phase purity, luminescent properties, and thermal stability were systematically investigated in this work. When monitoring the emission peak at 649 nm, Sr2InTaO6:Sm3+ phosphors present an absorption band due to the O2--> Sm3+ charge transfer. Under 407 nm excitation, Sr2InTaO6:5 mol%Sm3+ phosphor presents four emission peaks at 565, 603, 649, and 717 nm corresponding to the electron transition from 6G5/2 level to 6H5/2, 6H7/2, 6H9/2 and 6H11/2 levels, respectively. The best doping concentration of Sr2InTaO6:xSm3+ is optimized as x = 5 mol%. The chromaticity coordinates of Sr2InTaO6:xSm3+ 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, Ra = 93) with CIE (Commission International de L ' Eclairage) coordinates (0.346, 0.349). Therefore, Sr2InTaO6:Sm3+ phosphors have excellent luminescent properties and promising application prospects.

Automated summary

Novel double perovskite Sr2InTaO6:Sm3+ phosphors were synthesized and their phase purity, luminescent properties, and thermal stability were investigated. Under 407 nm excitation, the phosphors exhibited four emission peaks at 565, 603, 649, and 717 nm. The optimal doping concentration was determined to be 5 mol%. The prepared phosphors showed high color stability and excellent thermal stability. The WLED fabricated with the phosphors had a low correlation color temperature and a high color rendering index, indicating promising application prospects.