From Er3+:4I11/2 level there're two emissions, one is ~2.7 μm emission (Er3+:4I11/2 →4I13/2) and the other is ~1 μm emission (Er3+:4I11/2 →4I15/2).
So my question is in order to get the luminescence lifetime of Er3+:4I11/2 level, can I measure the luminescence lifetime of ~1 μm emission? And does this luminescence lifetime equal to that of ~2.7 μm emission?
Thank you!
Hi,
Emission from the specific excited state has equal lifetimes for each electronic transition.
If there are multiple sites, you may observe diffeent lifetime for the two transitions, as the weight of the contributions to the two transitions from each site may vary.
Hi there, Chang-Kui,
Why so? In my opinion we will observe overall multiexponential decay describing the sum of PL kinetics from each site, but decay for both transitions has to be the same.
Hi Anatoly,
"we will observe overall multiexponential decay describing the sum of PL kinetics from each site" is agreed. However, the branching ratio may vary from ions in one site to another, so you may find the effective decay time can be different (to some extend).
I supposed the question was about experimental lifetimes. Indeed, the effective ones may vary considerably.
If the emission is from the same state then the lifetime will be the same, except for (i) self-absorption at the highest energy transition which lengthens the lifetime, and (ii) the change of refractive index of the crystal for near and mid IR wavelengths.
The effective lifetime of f-f transition is given by:
τeff = 1/(AED+AMD), where AED and AMD are calculated probabilities of electric dipole and magnetic dipole transitions respectively. You may find the detailed description in the paper "Features of spectral properties of Sm3+ complexes with dithia- and diselenophosphinate ligands".
By effective lifetime, I meant the time for the intensity to decay to 1/e. This is needed for the case of non single-exponential decay of intensity.
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