Consider a case where 3 thin film samples have bandgap PL emission intensities 1, 2 and 3 and defect emission intensities 1, 1, and 1. (ie: The PL spectrum have been normalized to the defect emission intensity)
If we were to perform TRPL measurements on the band gap emission, will the sample with bandgap emission intensity 3 always have the longest carrier lifetime?
The mechanisms causing short carrier lifetime compete with recombination with photon emission.
Simply put, emission intensity (quantum yield) and lifetime are proportional. The proportionality constant is radiative rate constant. Unless the radiative rate constant for two different samples are same we cannot say that increased emission will lead to longer lifetime.
Nikolay Pavlov Mohammad Soroosh Tuhin Khan Thank you for your insights! If all samples are of the same material, but have been annealed under 3 different conditions to have different extend of defect passivation, is it still reasonable to assume that the radiative rate constant are the same, and the increased band edge PL emission intensity correlates to increased TRPL carrier lifetimes?
In general PL lifetime and intensity are correlated.
See for instance equations (for molecules) in:
Thesis Introduction to Electron Transfer
But it can depend on the material and the substrate, effects of oxygen, effects of moisture and other effects.
We have seen the reversed, low intensity, long lifetime for grain boundaries.
See:
https://doi.org/10.26434/chemrxiv.5484073.v2
But this later turned out to be a surface effect. (we later compared ITO vs glass). The coupling to the suface is stronger on ITO and is different for the grain boundaries.
If you have the measured data, intensity and lifetimes, than you can perhaps correlate them. And check what other people found for similar material and annealing.
René
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