Thermal stabilization and energy transfer in narrow-band red-emitting Sr[(Mg2Al2)1−y(Li2Si2)yN4]:Eu2+ phosphors. Issue 22 (24th May 2018)

• Record Type: Journal Article
• Authors: Leaño, Julius L.; Lesniewski, Tadeusz; Lazarowska, Agata; Mahlik, Sebastian; Grinberg, Marek; Sheu, Hwo-Shuenn; Liu, Ru-Shi
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 22(2018)
• Page Start: 5975
• Page End: 5983
• Publication Date: 2018-05-24
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7tc05613c
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : The Li–Si substitution in Sr[Mg2 Al2 N4 ]:Eu 2+ enhanced thermal stability and tuned the emission further gaining insight into the energy transfer mechanism. Abstract : Cuboid-coordinated nitridomagnesoaluminate Sr[Mg2 Al2 N4 ]:Eu 2+ and a solid solution of Sr1− x [(Mg2 Al2 )1− y (Al2 Si2 ) y N4 ]:Eu x 2+ were prepared using all-nitride precursors by gas pressure sintering. X-ray diffraction (XRD) data of the phosphors were validated by Rietveld refinement of synchrotron X-ray powder XRD data with the space group I 4/ m indexed to a tetragonal crystal system. The 7 Li solid-state magic-angle spinning nuclear magnetic resonance (ss-MAS-NMR) data prove the successful incorporation of the Li + –Si 4+ couple. The blue-light excitable property with the excitation band peaking at 460 nm gave rise to emission at 620–630 nm at x = 0.004, with a full-width-at-half-maximum of ∼77 nm. The inhomogeneous broadening of the Eu 2+ luminescence in the system due to the effective energy transfer from one activator to another was observed which concurrently resulted in spectral peak shifts from ∼615 nm to ∼680 nm as a function of the amount of Eu 2+ . The Li + –Si 4+ -tuned solid solution increased the emission intensity without significantly shifting the emission wavelength. Such a phenomenon was accompanied by an improvement in thermal stability from Δ = 965 cm −1 for y = 0, to Δ = 1365 cm −1 for y = 0.1 wherein Δ corresponds to the activation energy from the 5d states to the conduction band. The simple gas pressure sintering strategy using all-nitride starting materials resulted in the desired blue light-excitable narrowband red emitting thermally stabilized phosphor.