Luminescence properties of high thermal stability Sr2LaNbO6: xLn3+(Ln3+=Eu3+/Sm3+) phosphors with double-perovskite structures

A series of novel single-phased niobate phosphors Sr2LaNbO6:xLn(3+)(Ln(3+) = Eu3+/Sm3+) (SLNO:Ln(3+)) with red light emission was successfully synthesized by a conventional solid-state method and characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction, and photoluminescence. The phosphors showed high thermal stabilities, and at 423 K they still retained 60.7% and 80.7% emission efficiencies for the Eu3+ and Sm3+ variants, respectively. There is a difference in decay time between Eu3+ and Sm3+ due to the energy transit in different energy levels. The crystalline structure was described as a double-perovskite structure with several hexa-coordinated sites. The synthesized Eu3+ phosphor had more favorable characteristics for LEDs and a prototype device was fabricated with blue-green commercial LED phosphors, Sr2LaNbO6:0.13Eu(3+), and a 395 nm-emitting InGaN chip, which exhibited warm white light, with a color temperature of 4833 K. The current study demonstrates that Sr2LaNbO6:0.13Eu(3+) can be a potent red phosphor in LED applications.