Photoluminescence properties of certain trivalent RE ions (Dy/Sm/Eu) activated NaSrBi2(PO4)3 phosphors and cool to warm white color tuning in Dy3+-Sm3+ and Dy3+-Eu3+ codoped NaSrBi2(PO4)3 phosphors for indoor lighting applications

Abstract

The host NaSrBi2(PO4)3 (abbreviated as NSBP) and the rare earth ions (RE3+) Dy3+/Sm3+/Eu3+ doped and codoped NSBP phosphors were prepared by a simple solid state reaction method. The phase identification and the morphological nature were studied by Powder XRD and HRSEM characterization tools respectively. The band gap of the host and RE3+ ions (Dy3+/Sm3+/Eu3+) doped phosphors were deduced from the diffused reflectance (DR) spectral data. The PLE spectra, the PL spectra and the energy transfer (ET) mechanism of Dy3+/Sm3+/Eu3+ doped and Dy3+-Sm3+, Dy3+-Eu3+ codoped NSBP phosphors were studied. The lifetime of the Dy3+/Sm3+/Eu3+ ions in NSBP was in the order of millisecond. The temperature dependent photoluminescence (TDPL) of the optimized phosphors were recorded from 23 °C to 210 °C, showed good thermal stability at 150 °C. The PL emission from the NSBP-xDy3+ phosphors found very closer to the ideal white region. The Sm3+ and Eu3+ doped NSBP phosphors exhibited excellent color coordinates and color purity when compared to the commercial phosphors. Combining the PL emission of the optimized NSBP-0.09Dy3+ phosphor with Sm3+ and Eu3+ ions separately, warm white emission was obtained when excited in the NUV region. Thus the prepared phosphors NSBP-0.09Dy3+,uSm3+ and NSBP-0.09Dy3+,vEu3+ might have promising applications in NUV excitable warm white light emitting diodes fabrication.