Ion migration has been reported to be one of the main reasons for hysteresis in the current-voltage (J-V) characteristics of perovskite solar cells. We investigate the interplay between ionic conduction and hysteresis types by studying Cs0.05(FA0.83MA0.17)0.95Pb(I0.9Br0.1)3 triple-cation perovskite solar cells through a combination of impedance spectroscopy (IS) and sweep-rate-dependent J-V curves. By comparing polycrystalline devices to single-crystal MAPbI3 devices, we separate two defects, β and γ, both originating from long-range ionic conduction in the bulk. Defect β is associated with a dielectric relaxation, while the migration of γ is influenced by the perovskite/hole transport layer interface. These conduction types are the causes of different types of hysteresis in J-V curves. The accumulation of ionic defects at the transport layer is the dominant cause for observing tunnel-diode-like characteristics in the J-V curves. By comparing devices with interface modifications at the electron and hole transport layers, we discuss the species and polarity of involved defects.

ACS
doi.org/10.1021/acs.jpclett.3c03146
J. Phys. Chem. Lett.
Hybrid Solar Cells

Tammireddy, S., Lintangpradipto, M., Telschow, O., Futscher, M., Ehrler, B., Bakr, O., … Deibel, C. (2024). Hysteresis and Its Correlation to Ionic Defects in Perovskite Solar Cells. J. Phys. Chem. Lett., 15(5), 1363–1372. doi:10.1021/acs.jpclett.3c03146