Lets say we have a room temperature PL spectrum. If an oxide material (eg: Cu2O) have very strong defect related PL emissions (O vacancies, Cu vacancies) and weak band-to-band PL emissions (but very narrow sharp peaks), does it mean that the material will perform poorly in a photovoltaic device?
Does strong defect-related PL emissions (O vacancies, Cu vacancies) imply a high recombination rate in the material?
Or is it more accurate to look at the carrier lifetime using time resolved photoluminescence (TRPL)?
Hello Helen,
Any radiative recombination is undesirable in photovoltaic energy havesting. But if you understand what is trapping the carriers, and prevent it the material may be useful. Besides, you need to trap the carriers anyways, but in addition they should be routed along the right pathway to use them in an external circuit. I would not just give up the material. Like you said, try to get time resolved data, not only in emission but also transient absorption. May be you can see what the carrier dynamics is before they land on the traps.
I would also recommand the time resolved investigation of the excitated electronic states. If the the lifetime is sufficient long, it might be good enough for carrier transport towards the electric contatcs of a solar cell device.
The widely studied Zn2SnO4 nanowires/ nanoparticles for sensitized solar cells does not shows band gap emission and instead have strong defect emission. we have done some similar studies on Zn2SnO4 nanowires which might be helpful for you.
Article Steady state and time resolved optical characterization stud...
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