Influence of Li dopants on thermoluminescence spectra of CaSO4 doped with Dy or Tm

Role of Li+ion in the luminescence enhancement of lanthanide ions: favorable modifications in host matrices

“…In addition to these, there are several other host matrices viz. Ba 2 GdNbO 6 :Eu 3+ /Dy 3+ ,Li + , 115 BaZn 2 (PO4) 2 :Sm 3+ ,R + (R ¼ Li, Na, K), 116 Ca 3 B 2 O 6 :Dy 3+ ,Li + , 117 CaSO 4 :Tm 3+ /Dy 3+ ,Li + , 118 (Y, Gd)BO 3 :Tb 3+ ,Li + , 119 YNb-TiO 6 :Eu 3+ ,Li + , 120 YBO 3 :Eu 3+ ,Li + , 121 Zn 2 SiO 4 :Yb 3+ ,Er 3+ , Li + /Bi 3+ , 122 SrB 4 O 7 :Eu 2+ ,Li + , 123 Lu 2 SiO 5 :Ce,Li + , 125 Y 2 MoO 6 :Eu 3+ ,Li + , 126 NaSr-BO 3 :Tb 3+ ,Li + , 127 Sr 2 SiO 4 :Eu 3+ ,(Li + , Na + , K + ), 129 CaSnO 3 :Tb 3+ (Li + , Na + , K + ), 131 Gd 6 MoO 12 :Li + /Ln 3+ , 132 Y 2 SiO 5 :Pr 3+ ,Li + , 133 Y 2 Zr 2 O 7 : Dy 3+ ,Li + , 134 Li x Ca 1À2x Eu x Si y Mo 1Ày O 4 , 136 Ca 2 BO 3 Cl:Sm 3+ (Li + , Na + , K + ) 139 and CaSi 2 O 2 N 2 :Eu 2+ ,Dy 3+ ,Li + , 140 etc. in which the role of Li + in luminescence properties has also been investigated.…”

Remarkable flux effect of Li-codoping on highly enhanced luminescence of orthosilicate Ba2SiO4:Eu2+ phosphors for NUV-LEDs: autonomous impurity purification by eutectic Li2CO3 melts

“…[1][2][3][4][5][6][7][8][9][10][11][12] It is generally accepted that the Li + ions doped in the host lattices play important roles in the enhanced luminescence properties of the phosphors. The enhanced luminescence of the Li-codoped phosphors has been explained as follows: (i) copresence of Li + ions favorably modies the local structure of the activator ions and their special distribution; [1][2][3][4] (ii) codoping of Li + ions creates oxygen vacancies which might act as a sensitizer for the energy transfer to activator ions; 5,7,9,10 (iii) Li precursors such as Li 2 CO 3 or LiF act as a ux which promotes incorporation of the activator ions into the host lattice and also enhances crystal growth during the ring process at high temperatures; 5,6,12 and (iv) Li-codoping provides the product particles with a morphology that is more desirable in reducing internal reection. 5,6 Among these possible mechanisms of luminescence enhancement by Li-codoping, the ux effect (i.e., (iii)) has been found to play a minor role.…”

The Role of Sintering in the Synthesis of Luminescence Phosphors

“…However, Dy 3+ could be incorporated in CaSO 4 lattice only by recrystallization in H 2 SO 4 medium. A recent study [7] has shown that Li coactivator could be successfully introduced in CaSO 4 :Dy/Tm at a concentration of 0.06% during a subsequent step of cold pressing at RT and sintering of the pellets at 700 0 C. A number of alternative lithium compounds have been used in this role and they include Li2CO3, LiCl, LiF, Li2B4O7 and Li2SO4. Addition of lithium significantly shifted the major TL peak of CaSO 4 :Dy/Tm from 220°C down to 120°C.…”