Optical spectroscopy of Eu3+ ions doped in YAl3 (BO3)4 crystal

Synthesis, characterization and optical spectroscopy of GdPO4:Er3+

“…[ 31,32 ] Judd–Ofelt theory based on absorption spectra was described in detail in our previous study. [ 33,34 ] The electrical dipolar transition line strength S (J→J′) between J and J′ states can be calculated using the known relationship (eqn 5): where N 0 is the Er 3+ concentration in the host (7.129 × 10 22 ions cm −3 ); is the mean wavelength of the transition and (2J + 1) is the multiplicity of the ground state; Γ are the integrated absorbances; c is the velocity of light in a vacuum, e is the electric charge, d is the sample thickness (0.11 cm) and h is Planck's constant (6.63 × 10 −27 erg.s), n (1.97) is the refractive index.…”

Eu3+ ions as a crystal-field probe for low-symmetry sites in doped phosphors – a case study: Eu3+ at triclinic sites in Li6RE(BO3)3 (RE = Y, Gd), YBO3 and ZnO and at trigonal sites in YAl3(BO3)4

“…, Y 2 O 3 , 7,8 YVO 4 , 9 Y 2 O 2 S, 10 and YAl 3 (BO 3 ) 4 . 11–13 Due to the hypersensitivity of Eu 3+ ions 5,6,12 to the site symmetry, Eu 3+ is often employed as a luminescent probe in order to investigate the occurrence of Eu 3+ ions in non-equivalent double-site structures, e.g. , Y 2 O 3 , 7,8 Lu 2 O 3 , 14 YBO 3 , 15 and ZnO.…”

“…19 Hence, erroneous assignment of the observed lines and/or identification of J multiplets and determination of the corresponding wave functions diminish the validity of J–O intensity analysis. 12 Furthermore, the J–O intensity parameters, denoted as Ω k ( k = 2, 4, 6), depend on the local environment around the RE 3+ ion, as well as are largely related to the covalency of metal (M)–ligand (L) bonds and distortions around RE 3+ sites. 33…”

“…16–18 For comparative analysis, we consider also the YAl 3 (BO 3 ) 4 crystal having a hexagonal structure with trigonal sites. 11,12 Most importantly, due to the possible existence of multiple minima on the error surface of the parameter space for the low-symmetry host-dopant systems, 36 reliable fittings of the observed energy levels are rather hard to achieve, see, e.g. , ref.…”

“…3 The emission around 610-630 nm is due to the ED transition 5 D 0 -7 F 2 , when Eu 3+ ions occupy lower symmetry sites with no inversion (point symmetry groups: C 2 /D 2d /C 3v /D 3 ) in red-emitting phosphors, 6 as e.g., Y 2 O 3 , 7,8 YVO 4 , 9 Y 2 O 2 S, 10 and YAl 3 (BO 3 ) 4 . [11][12][13] Due to the hypersensitivity of Eu 3+ ions 5,6,12 to the site symmetry, Eu 3+ is often employed as a luminescent probe in order to investigate the occurrence of Eu 3+ ions in non-equivalent double-site structures, e.g., Y 2 O 3 , 7,8 Lu 2 O 3 , 14 YBO 3 , 15 and ZnO. [16][17][18] This probe enables inferring the distortions of the ligand environment and site symmetry of each dopant site, and hence, sheds more light on the crystallographic structure of the host matrix.…”