Luminescence Spectra of β-SiAlON/Pr³⁺ Under High Hydrostatic Pressure

Abstract

In this contribution, steady-state and time-resolved photoluminescence spectra of β-Si 5.9 Al 0.1 O 0.1 N 7.9 /Pr 3+ 0.016 obtained at high hydrostatic pressures up to 260 kbar are presented. At ambient pressure, excitation spectra of the β-SiAlON/Pr 3+ luminescence consist of sharp lines in the spectral region of 20000−22200 cm −1 related to the 3 H 4 → 3 P 0,1,2 transitions and a broad band with two maxima peaking at 30300 and 35700 cm −1 , which are related to the ionization of Pr 3+ ions occupying two different crystallographic sites in the β-SiAlON lattice. In both sites, the luminescence spectra consist of the dominant 1 D 2 red emission and 3 P 0 blue emission of Pr 3+ ions. The intensity of luminescence related to transitions from the 3 P 0 state and the respective decay time gradually decreases when the pressure increases. The intensity of emission from the 1 D 2 state is independent of the pressure and remains strong over the entire pressure range. Weak dependence of the Pr 3+ emission on applied pressure can be related to the covalent and strong Pr−N bonds and specific location of Pr 3+ ions occupying empty lattice points in β-SiAlON.

Structural phase transitions and photoluminescence properties of oxonitridosilicate phosphors under high hydrostatic pressure

“…Properties of complex consisting of Eu 2+ ions and its negatively charged coordination sphere can be described using crystal field approximation in such case high hydrostatic pressure causes the increase of the energies of the 4f  7 , 4f  6 5d 1 electronic configuration with respect to the host bands energies and the increase of the 4f  6 5d 1 levels splitting2425. The superposition of these effects are seen as a pressure-induced diminishing of the energy of luminescence related to the 4f  6 5d 1  → 4f  7 transition.…”

Multiple doping structures of the rare-earth atoms in β-SiAlON:Ce phosphors and their effects on luminescence properties

“…3(b)) but show different crystallographic positions. 18,21,34 Apart from different interstitial incorporation of Ce in the β-SiAlON crystal structure, substitional doping of Ce for Si(Al) has also been observed as can be seen in Fig. 4(a)) confirms two kinds of interstitial occupation sites while B-site seems more favorable than A-site for Ce doping in β-SiAlON crystals.…”

“…Here, the exact locations and coordinations of Ce rare-earth atoms in β-SiAlON structure have been examined by using an atom-resolved Cs-corrected scanning transmission electron microscope. Very recently, Mahlik et al 21 presented interesting luminescence spectra of Pr 3+ -doped 5 rather than powder samples for the present study owing to that the former could be processed to ultra-thin foils through mechanical polishing and ion-milling treatment. Chemical valences and stability of the doping Ce ions at different occupation sites have been evaluated by the density functional calculations.…”

“…Very recently, Mahlik et al 21 presented interesting luminescence spectra of Pr 3+ -doped 5 rather than powder samples for the present study owing to that the former could be processed to ultra-thin foils through mechanical polishing and ion-milling treatment. Very recently, Mahlik et al 21 presented interesting luminescence spectra of Pr 3+ -doped 5 rather than powder samples for the present study owing to that the former could be processed to ultra-thin foils through mechanical polishing and ion-milling treatment.…”

“…Then Kimoto et al 19 directly observed a single dopant in the channel of β-SiAlON:Eu phosphor by scanning transmission electron microscopy (STEM). 18,21,34 Apart from different interstitial incorporation of Ce in the β-SiAlON crystal structure, substitional doping of Ce for Si(Al) has also been observed as can be seen in Fig. However, both of their observations were carried out unexceptionally along the [001]…”