Structural and Spectroscopic Characterization of Tb³⁺‐Doped MgAl₂O₄ Spinel Ceramics Fabricated by Spark Plasma Sintering Technique

Abstract

Spark plasma sintering (SPS) technique is successfully used for the preparation of magnesium aluminate spinel ceramics doped with different concentrations of Tb3+ ions. Structural, morphological, optical, and photoluminescence (PL) characterization are conducted. It is demonstrated that the redshift in the absorption spectra is possibly due to the energy gap between the valence and conduction bands reducing and the formation of a higher concentration of nonbridging oxygen with an increase in the concentrations of Tb3+ ions in MgAl2O4 ceramics. The PL spectrum excited by nitrogen laser consists of a broad emission band with a maximum at λem ≈ 400 nm and a series of emission bands in the 400–700 nm spectral range responsible for Tb3+ ions. In the “blue” spectral region, the complex host centers such as oxygen vacancies are recorded. An increase in the terbium ion concentration does not lead to the effect of concentration quenching. Luminescence decay kinetics analysis for all ceramics samples is performed. The effect of terbium oxide on the optical, PL properties and luminescence decay kinetics of MgAl2O4 ceramics is discussed.

Er‐Doped MgAl2O4 Nanofilms Enabling Highly Efficient Near‐Infrared Electroluminescence from the Silicon‐Based MOS Devices Fabricated by Atomic Layer Deposition

“…[21,22] How-ever, previous research reported the Er 3+ ions could replace not only the tetrahedral positions of Mg 2+ ions but also the octahedral positions of Al 3+ ions, due to the defect accumulation in the spinel structure. [23,24] Particularly, due to the cluster of Frenkel defect pairs in MAO spinel, the occupation of cations (Mg 2+ or Al 3+ ) at diverse sites is changed and the O interstitials recombine with the vacancies, which result in the structure transformation from ordered spinel to disordered spinel and further to disordered rock-salt. [25,26] Therefore, except the substitution of Mg 2+ and Al 3+ ions, Er 3+ ions enter into the vacancy sites, [27] resulting in the subsequent difference in EL performance.…”

Extended Positron‐Trapping Defects in the Eu3+‐Doped BaGa2O4Ceramics Studied by Positron Annihilation Lifetime Method

“…[ 15–24 ] Nevertheless, doping of such ceramics not only leads to modification of their luminescent properties and changes in phase composition, but also causes structural transformation. [ 25–27 ] Such significant transformation of the inner structure in ceramics facilitates the formation of additional defect‐related free volumes. [ 28–33 ]…”

“…[15][16][17][18][19][20][21][22][23][24] Nevertheless, doping of such ceramics not only leads to modification of their luminescent properties and changes in phase composition, but also causes structural transformation. [25][26][27] Such significant transformation of the inner structure in ceramics facilitates the formation of additional defect-related free volumes. [28][29][30][31][32][33] Among the less conventional but promising methods to study the defect-related free volumes in solids of different structural types is positron annihilation lifetime (PAL) spectroscopy.…”

Preparation and fluorescence properties of MgAl2O4: Tb3+ nanorod-like phosphors

“…The MgAl 2 O 4 : 2% Tb 3+ phosphor presented the highest luminescence intensity, and the colour could be tuned by changing the Tb 3+ content (2 mol%). For the first time, Valiev et al [18,19] presented structural and spectroscopic investigations of MgAl 2 O 4 ceramics doped with different concentrations of Tb 3+ ions (0.1, 1 and 5 wt%) fabricated by spark plasma sintering (SPS). However, there are still the few reports on the luminescence regularity of MgAl 2 O 4 doped with higher concentrations of Tb 3+ ions.…”