Electrospinning fabrication and luminescence properties of Lu₂O₂S:Eu³⁺fibers

Solvothermal synthesis of columnar Gd2O2S:Eu3+ and a comparative study with columnar Gd2O3:Eu3+

“…The Judd‐Ofelt (J‐O) parameters were calculated by the emission spectra to understand the symmetry, coordination environment, and luminescence behavior of Eu 3+ ions in the Gd 2 O 2 S matrix. The analysis based on the Judd‐Ofelt parameters can be used to calculate the parity‐forbidden electric‐dipole radiative transition rates between different energy levels of rare‐earth ions . In this section, J‐O parameters include A 01 , A 02 , A 04 , Ω 2 , and Ω 4 were calculated and other radiative properties were predicted based on these parameters.…”

“…The analysis based on the Judd-Ofelt parameters can be used to calculate the parity-forbidden electric-dipole radiative transition rates between different energy levels of rare-earth ions. 9,34,37 In this section, J-O parameters include A 01 , A 02 , A 04 , Ω 2 , and Ω 4 were calculated and other radiative properties were predicted based on these parameters.…”

RE-Based Inorganic-Crystal Nanofibers Produced by Electrospinning for Photonic Applications

“…In fact, Eu 3+ ions, also possess a series of visible emission lines that originate from the 5 D 0 and 5 D 1 multiplets with good color-tuning properties [30,72,82], that make them very interesting for lightening applications. In fact, Eu-doped nanofiber mats have already been tested in realistic LED devices [32,34] and Eu 3+ is probably the mostly studied rare earth ion in nanofiber matrixes [1,13,19,29,30,32,34,35,37,41,42,45,47,48,51,[53][54][55]61,62,67,68,76,[79][80][81][82]84,[86][87][88][89]91,101,112] including some nanobelt structures [72] and hollow structures [82]. In most of these cases, diameter of the nanofibers was less than 300 nm, with a few exceptions [35,42,76].…”

“…In fact, the addition of Tm 3+-, Sm 3+or Tb 3+ions shifts the emission color from blue, to red, to green [51]. Since most of the emission lines originate from 5 D 0 reported lifetimes usually refer to the decay of this level and concentration-dependent values range from 0.5 ms to more than 5 ms in oxide hosts [30,35,37,45,47,53,55,[80][81][82]84,86,87,89] and from 7 to 12 ms in fluorides [13,19,29,112]. In very few cases the lifetime of the 5 D j levels with j > 0 has been reported.…”

“…For example in YVO 4 the lifetime of 5 D 1 is reported to be around 7.5 µs [89], in NaGdF 4 lifetimes of 5 D 3 , 5 D 2 , 5 D 1 are 2.38, 4.04, 6.36 ms, respectively and in GdF 3 lifetimes of 5 D 3 , 5 D 2 , 5 D 1 are 2.26, 3.58, 3.88 ms, respectively. Concentration optimization of the luminescence intensity yelds an optimum concentration of Eu 3+ ions usually in the range of 5-8% [47,53,54,72,89] before the onset of concentration quenching effects, but in some compounds such as Y 2 O 3 , Y 2 O 2 S and Lu 2 O 2 S lower values (around 3%) have been reported [55,82] and in Gd 2 O 3 no concentration quenching effects have been observed up to 10% Eu 3+ concentration. Moreover, in some cases polarized emission have been observed and characterized [76,81] and in Ca (Sr)Al 2 Si 2 O 8 persistent luminescence from Eu 3+ ions has been observed with a lifetime of 157.12 s. Some of these compounds possess bifunctional properties.…”