I seek help for perovskite UPS analysis for the Valence band and work function calculation. The sample preparation and if there are any critical things?
I have characterized my perovskite layer several times in different architectures; (Glass/Perovskite), (ITO/perovskite), (ITO/PTAA/Perovskite).
My SECO is in the range of 16.87eV but the valence band cut off is always higher (~1.6eV). The perovskite Eg~1.56eV. With these values, the Fermi level is above conduction band. I would appreciate your help in this regard. Thank you.
see
Influence of A-site Cation on the Open-Circuit Voltage of Efficient Perovskite Solar Cells: A case of Rubidium and Guanidinium Cations
Hi Asmat, could you post a picture of the UPS spectrum in question? There are a number of issues that could be the source of your issue. For example, have you collected a UPS spectrum of Au recently using the same parameters you collected your spectrum with? If the photoelectron onset is not calibrated to zero for gold it will offset all measurements. Another issue could be your choice of cutoff energy, so seeing how you did that would be helpful. Finally, do you know if your sample was charging before running UPS? Charging of the sample can really throw off your measurements.
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