Photo‐ and Cathodoluminescent Properties of Erbium‐Doped Thiogallates

Abstract

In order to determine the ability of erbium to give a saturated green color, luminescent properties of Er3+ in the thiogallates MGa2S4 false(M=normalCa,normalSr,normalBafalse) MLaGa3S7 false(M=normalCa,normalSrfalse) , and La5/3Ga3S7 have been investigated. For efficient u.v. or cathodic excitation, the erbium charge transfer band must lie at longer wavelength than the lattice absorption edge; this is the case for the MGa2S4 phases. Three processes can contribute to the population of the green emitting levels, 2H11/2 , 4S3/2 : direct transfer from the charge transfer band, multiphonon transitions, and cross‐relaxations. Multiphonon relaxation probabilities increase in the sequence CaGa2S4<SrGa2S4<BaGa2S4 . The green emission of BaGa2S4:normalEr is strongly saturated (trichromatic coordinates: x=0.275 , y=0.703 , under cathode‐ray excitation).

Photoluminescence spectra of rare earth doped CaGa2S4 single crystals

“…These spectra differ from those of the other RE doped thiogallates in a point that new lines appeared with increase of temperature (here after we say it as a 'positive' temperature dependence), in contrast that the lines at low temperature diminished or disappeared (we call it as a 'negative' one) in the other cases. Garcia et al already measured Er doped thiogallates at 300 K [11]. Our data at the same temperature agreed very well with theirs, and the assignments according to them are shown in Fig.…”

Photoluminescence properties of a new Eu2+-activated CaLaGa3S7 yellowish-green phosphor for white LED applications

“…Other studies include those by Flahaut who found that MLaGa 3 S 7 (M ¼Ca, Sr) and L 10/3 Ga 6 S 14 (L ¼La, Ce) thiogallates had the same tetragonal structure of the melilite type [8] and that of Fouassier who investigated the Er 3 þ -doped CaLaGa 3 S 7 , SrLaGa 3 S 7 , and La 5/3 Ga 3 S 7 thiogallates. Fouassier found that these melilitetype phosphors showed the green characteristic emission from Er 3 þ [9].…”

Luminescence properties of a new blue-emitting phosphor Ce3+-doped CaLaGa3S7

“…The MLaGa 3 S 7 (M = Ca, Sr) and L 10/3 Ga 6 S 14 (L = La, Ce) thiogallates have been reported to exhibit the same tetragonal structure of the melilite type [9]. Fouassier et al investigated the Er 3+ -doped CaLaGa 3 S 7 , SrLaGa 3 S 7 , and La 5/3 Ga 3 S 7 thiogallates, and found that these melilite-type phosphors showed the green characteristic emission from Er 3+ [10].…”