While doing TRPL of MAPbI3 thin film on corning glass substrates it is difficult to get a good intensity of emission.
At best, an intensity of only about 100counts is observed with a 405nm laser for the film thickness of ~400nm. However, high-intensity PL peaks are observed in steady-state PL measurements.
What may be the possible reasons for this and what are the points to be taken care of to get correct data?
One of the possible reasons could be an alignment of the incident beam through the optical components on your sample. Secondly, you may need to move the position of your sample, which is likely burnt or degraded by the laser beam.
Finally, you could use a well-known fluorescent sample to test your system before measuring your samples.
Hope it helps.
Dear Pilik Basumatary , in addition to Xuhua Wang ´s suggestions you might also play with the laser pulse, probably both the laser pulse duration and the laser pulse energy. Your observation about a high intensity PL with a steady state PL (continous laser) is reasonable, you are sending continously excitation photons and therefore the PL photons are continually released from the sample, so the peaks show a high intensity due to photon accumulation. With a pulse you just excite for a moment your sample with a limited amount of excitation radiation, and so it is normal your peaks show lower intensities. Increasing the pulse energy (density of photons by pulse) can cause sample burning as pointed Xuhua.
Time-Correlated Single Photon Counting (TCSPC) is a useful way to overcome some problems of common TRPL, as indicated in the followed link:
https://www.picoquant.com/applications/category/materials-science/time-resolved-photoluminescence
Hope this helps. Good luck with your research and best wishes!
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