Luminescence properties and energy transfer of Bi3+/Eu3+-codoped Ca10(PO4)6F2 phosphors

Enhanced luminescence intensity of novel red-emitting phosphor -Sr3Lu2(BO3)4:Bi3+,Eu3+ via energy transfer

“…where I(t) is the intensity at time t. In the inset of Figure 13, increases, the τ of Bi 3+ decreases which confirms the energy is successfully transferred from the sensitizer to the activator [9,16]. The schematic energy transfer diagram between Bi 3+ and Eu 3+ is presented in Figure 14.…”

“…Thus, it is very essential to search for new red phosphors that can be efficiently excited at around 400 nm [8]. Eu 3+ rare earth ions have drawn much attention of scientists in obtaining a redemitting due to its lowest excited level 5 D 0 of the 4f 6 configuration which is located below the 4f 6 5d configuration and it principally displays very sharp red emission lines at 5 D 0 -7 F 2 transition around 610~618 nm [8,9]. Most of the red-emitting phosphors are efficiently excited at around 393 nm [10,11] originating from 7 F 0 -5 L 6 transition which is parity forbidden therefore it exists as a sharp peak and cannot absorb the excitation energy efficiently.…”

Effect of [PO4]3−/[VO4]3− substitution on the structure and luminescence properties of Ca5[(P,V)O4)]3F:Eu3+ phosphors

“…In order to determine the optimum Eu 3+ doping concentration, Figure 3 gives the A c c e p t e d M a n u s c r i p t 7 coordinated to six oxygen and one fluoride atom [13]. As reported, the intensity of transitions between different J levels, for example the intensity ratio (R) of electric dipole transition to magnetic diploe transition (I R /I O ) depends on the symmetry of the local environment of the Eu 3+ activators and can be described in terms of Judd-Ofelt theory [14].…”

Tunable luminescence in Bi3+ and Eu3+ co-doped Sr3AlO4F Oxyfluorides phosphors

“…Among s 2 -sp transitions, it is known that the transitions of the 1 S 0 ground state to the 3 P 0 and 3 P 2 excited states are strongly forbidden, whereas the 1 S 0 -3 P 1 and 1 P 1 transitions can be observed owing to spin-orbital coupling [13][14][15][16]. Bi 3 þ activators are still being explored because of their structureless bands, as well as indefinite site symmetries [17]; furthermore, Bi 3 þ ions can act as sensitizers to enhance the emission of rare-earth activators and transfer energy to activators exhibiting color-tunable emission in various luminescent hosts such as divalent cation tungstates (ZnWO 4 ), molybdates (CaMoO 4 ), or phosphates (Ca 10 (PO 4 ) 6 F 2 ) [18][19][20].…”