A study on structural and luminescence properties of novel orange-red emitting Sm3+ doped Sr3LiSbO6 nanorod phosphor with high color purity for W-LEDs

Abstract

Being a simple synthesis technique, solid state reaction (SSR) method seldom generates 1D nanorod structured phosphors. In this article, we present a systematic study on the structural, morphological and spectroscopic properties of double perovskite type Sr3LiSbO6:Sm3+ phosphors prepared by the conventional SSR method. X-ray diffraction (XRD) analysis confirm the successful synthesis of hexagonal structured Sr(3−x)LiSbO6:xSm3+(x = 0,0.06,0.08,0.1,0.2,0.4 mol) phosphors and Fourier-Transform Infrared spectra (FTIR) revealed the molecular vibrations present in the samples. The surface morphology was confirmed by Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) analysis. The TEM images illustrate the one – dimensional nanorod structure of the phosphor with an average diameter of 35 nm and length of 350 nm. In photoluminescence (PL) spectroscopy, under an excitation of 406 nm the characteristic emissions at 564, 601, 649 and 710 nm, which correspond to the transitions from 4G5/2 to 6H5/2, 6H7/2, 6H9/2 and 6H11/2 respectively of Sm3+ were obtained with strong orange - red emission at 601 nm. The concentration quenching was observed at x = 0.1 mol and the critical distance for energy transfer between Sm3+ ions was calculated to be 14.32 Å. The energy transfer mechanism was determined to be dipole-dipole interaction. The decay analysis confirms the shorter life time of the activator ions in the microseconds (µs) range. The estimated CIE coordinates are (0.6057, 0.397) in the warm CCT region with 100 % color purity. Hence these results suggests that Sm3+ doped Sr3LiSbO6 to be a potential orange-red nanorod phosphor in the design of various photonic devices such as phosphor converted LEDs (pc- LEDs).