Luminescence and energy transfer in K3GdF6:Pr3+

Abstract

Single phase, polycrystalline K 3 GdF 6 compound containing 1 at.% of Pr 3+ was prepared and its luminescent properties were investigated in the 10-300 K temperature region. The temperature weakly influences the 3 P 0 emission, whereas the 1 D 2 emission decreases from 520 s at 10 K to 219 s at 290 K due to temperature dependent self-quenching effect. Excitation spectra provide evidence that the energy is transferred from the 5d levels of Pr 3+ to the energy levels belonging to the 4f 7 configuration of Gd 3+ .

Spectroscopic properties and upconversion in Pr3+:YF3 nanoparticles

“…For the lowest concentration (0.05%), the fluorescence intensity decreases with time following a nearly exponential function with a time constant of 33 ms. This value is well within the established range for the 3 P 0 lifetimes, measured for Pr 3+ in low concentration fluoride materials (47 ms in LaF 3 , 16,17 63 ms in K 3 GdF 6 , 18 33 ms in K 5 PrLi 2 F 10 , 19 40 ms in LiKYF 3 , 20 and 40 ms in KY 3 F 10 21 ). Few experimental values are available for the 3 P 0 (Pr 3+ ) lifetime in YF 3 because most studies concern photon cascade emission.…”

“…This value is in the range of the calculated value (285 ms) 22 and in the range of the 1 D 2 lifetimes determined in other fluoride materials. 18,19,21,30 With increasing concentration, the non-exponential character is more pronounced and the asymptotic lifetime decreases from 240 ms for the sample doped with 0.05% to about 52 ms for the highest studied concentration (5%). The asymptotic part of the decay, shown in Fig.…”

“…These values are in agreement with typical values measured for the 3 P 0 (Pr) multiplet in other fluoride crystals. 14,18 Indeed the quantum efficiency of the visible emission for the 0.01% Pr doping level in YF 3 is 61%, and that of the 1% Pr doping level is as low as 17%. 15 In our case, the lifetime decrease from 10 to 300 K exceeds 50% of the low temperature value, and this confirms that, even at this low doping level, non-radiative processes play an important role.…”

Luminescence Dependence of Pr3+ Activated SiO2 Nanophosphor on Pr3+ Concentration, Temperature, and ZnO Incorporation

“…The temperature-dependent process is predicted when the condition of resonance is satisfied for transitions originating in thermally populated crystal field components of the ground states of acceptor ions. If not, the energy mismatch has to be assisted by lattice phonons while the temperature influences the rate of the cross relaxation . The decrease in the 1 D 2 lifetime with increasing temperature between 8 and 300 K cannot be assigned to nonradiative decay through multiphonon relaxation but rather to contribution of nonresonant cross relaxation process because the rate of multiphonon decay of 1 D 2 level is negligible in most of the hosts matrices compared with that of radiative decay due to the large energy gap between 1 D 2 and 1 G 4 . , The cross relaxation mechanism involved during the self-quenching process is believed to proceed through intermediate 1 G 4 and 3 F 4 levels.…”

“…36 The decrease in the 1 D 2 lifetime with increasing temperature between 8 and 300 K cannot be assigned to nonradiative decay through multiphonon relaxation but rather to contribution of nonresonant cross relaxation process because the rate of multiphonon decay of 1 D 2 level is negligible in most of the hosts matrices compared with that of radiative decay due to the large energy gap between 1 D 2 and 1 G 4 . 14,36 The cross relaxation mechanism involved during the self-quenching process is believed to proceed through intermediate 1 G 4 and 3 F 4 levels. 3+ Ions in SiO 2 .…”