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Elucidating the Impact of Charge Selective Contact in Halide Perovskite Through Impedance Spectroscopy

preprint
submitted on 28.08.2019, 08:54 and posted on 29.08.2019, 18:15 by Mohd Taukeer Khan, Manuel Salado, Abdullah R. D. Almohammedi, Samrana Kazim, Shahzada Ahmad

The electron and hole selective contact (SC) play a pivotal role in the performance of perovskite solar cells. In order to separate the interfacial phenomenon from bulk, the influence of charge SC was elucidated, by means of impedance spectroscopy. The specific role played by TiO2 and Spiro-OMeTAD as electron and hole SC in perovskite solar cells was investigated at short circuit condition at different temperatures. We have probed MAPbI3 and (FAPbI3)0.85(MAPbBr3)0.15 and elucidated parameters such as charge carrier mobility, recombination resistance, time constant and charge carrier kinetics in perovskite layer and at the interface of perovskite/SC. Charge carrier mobility in mixed perovskite was found to be nearly two order of magnitude higher as compared to MAPbI3. Moreover, the carrier mobility in devices with only electron SC was found to be higher as compared only hole SC. The charge accumulation at TiO2/perovskite/Spiro-OMeTAD interfaces were studied via frequency dependent capacitance, revealing higher charge accumulation at perovskite/Spiro-OMeTAD than at TiO2/perovskite interface. By performing varying temperature frequency dependent capacitance measurements the distribution of density of state within the bandgap of the perovskites, the emission rate of electrons from the trap states and traps activation energy was determined.

Funding

EU H2020 Excellence

History

Email Address of Submitting Author

shahzada.ahmad@bcmaterials.net

Institution

BCMaterials-Basque center for materials, applications & nanostructures

Country

Spain

ORCID For Submitting Author

0000-0002-1218-2556

Declaration of Conflict of Interest

no conflict of interest

Version Notes

pre accepted version

Exports