Lifetime measurements in Eu2+-doped host lattices

Luminescent properties of Eu2+ and Ce3+ ions in strontium litho-silicate Li2SrSiO4

“…Eu 2 + luminescence is usually due to 4f 6 5d-4f 7 interconfigurational transitions, which lead to a rather broad emission whose spectral position depends strongly on the chemical nature of the crystal. The maximum of the Eu 2 + 4f 6 5d-4f 7 [20,21]. In all the cases the emission bands are broad and the corresponding Stokes shifts are very large, ranging from $ 7500 cm À 1 for BaSiO 3 :Eu 2 + , Sr 2 LiSiO 4 F:Eu 2 + and up to 12,000 cm À 1 for Ba 2 Mg(BO 3 ) 2 :Eu 2 + .…”

“…Despite the emission maximum of Li 2 SrSiO 4 :Eu 2 + is in between those of Sr 2 LiSiO 4 F:Eu 2 + (535 nm), BaSiO 3 :Eu 2 + (550 nm) and Ba 2 LiB 5 O 10 :Eu 2 + (620 nm), this luminescence shows the characteristics of the Eu 2 + 4f 6 5d-4f 7 ( 8 S 7/2 ) emission. The red shift with the respect to the lowest excitation band is relatively small (3400 cm À 1 ), the decay time (t¼1.07 ms) is typical for 4f 6 5d-4f 7 transitions of Eu 2 + in inorganic compounds [21].…”

“…In all the cases the emission bands are broad and the corresponding Stokes shifts are very large, ranging from $ 7500 cm À 1 for BaSiO 3 :Eu 2 + , Sr 2 LiSiO 4 F:Eu 2 + and up to 12,000 cm À 1 for Ba 2 Mg(BO 3 ) 2 :Eu 2 + . Poort et al [20,21] and later Dorenbos [22] pointed out that these long-wavelength emissions are possibly not related to the 4f 6 5d-4f 7 transitions of Eu 2 + ions, but may be due to an absolutely different process, namely radiative decay of an impurity trapped exciton. This interpretation implies that excitation into the Eu 2 + 4f 7 -4f 6 5d bands leads to ionization of Eu 2 + ions and the formation of an exciton-like state, which consists of a bound electron hole pair with the hole localized on the Eu 3 + ion and the electron delocalized on the nearest-neighbor cations.…”

Controlling of Structural Ordering and Rigidity of β-SiAlON:Eu through Chemical Cosubstitution to Approach Narrow-Band-Emission for Light-Emitting Diodes Application

“…An evident increase in luminescence decay time with an increase in monitored luminescence wavelength supports this conclusion. 37 In addition, the decay curves of β-SiAlON:Eu (529) and β-SiAlON:Eu (540) were also measured at RT ( Figure S10 and Table S3). The obtained lifetimes show the same trend as that measured at 10 K. The decay time of the sharp lines as well as broad band for both samples are in the 0.6-1.2 μs range, which means that the observed luminescence is related to parity-allowed transitions from the excitated states of electronic configuration 4f electronic configuration create the seven electronic levels: 7 F0-7 F6, analogous to the Eu 3+ which does not interact with the lattice ions since they are screened by 5s 2 5p 6 electrons.…”

Eu2+luminescence in strontium aluminates

“…48 The l 3 dependence of the decay time yields a value of about 0.8 ms for the 445 nm emission. The shorter decay time observed, 0.4 ms, indicates that energy transfer takes place, shortening the decay time.…”