Emanating cool white light emission from novel down-converted SrLaAlO4:Dy3+ nanophosphors for advanced optoelectronic applications

To improve the current multi-phased white-LEDs, novel down-converted Dy3+ doped layered perovskite SrLaAlO4 nanophosphors emitting cool white light were successfully fabricated by urea assisted solution combustion approach. X-ray diffractometry and Rietveld refinement revealed the 14/mmm (139) space group of tetragonal phase in doped samples (SrLa(1-x)DyxAlO4 (x = 0.01-0.10)). Morphological studies reported the nanocubic crystals (45-55 nm) while their nanocrystalline nature and (101) crystal plane was depicted by selected area electron diffraction patterns. Elemental composition of nanomaterials was detected effectively via energy dispersive X-ray analysis. The vibrational metal-oxygen bonding in the sample was confirmed by FT-IR results. Photoluminescence spectra, on near UV excitation, showed two intense bands of blue and yellow color at 484 and 574 nm subjected to transition from F-4(9/2) -> H-6(15/2) and H-6(13/2), respectively. Maximum emission intensity was noticed for 5.0 mol% amount of dopant (Dy3+) ions. Decay life time, band gap and refractive index of optimized sample were noted as 0.413 ms, 4.98 eV and 1.736, respectively. CCT value (7418 K), color purity (23.02 x 10(-2)) and CIE coordinates (0.308, 0.284) of SrLa0.95Dy0.05AlO4 nanophosphor were approximate to coordinates of commercial LEDs and National Television System Committee, which confirmed their excellent practicability in the advanced optoelectronic devices, especially single-phase WLEDs for the illumination purpose.