Proceedings of Perovskite Thin Film Photovoltaics (ABXPV17)
Publication date: 18th December 2016
The steady-state current-voltage relation of a solar cell (j-V) provides its characteristic power conversion efficiency in long-term operation under sunlight. However, measured curves on the same sample may vary depending on the magnitude, rate, and direction of the scanning potential, resulting in hysteretic effects that make the extracted efficiencies unreliable. In spite of the many hypothesis reported in the literature, this issue is still unclear and open to further research.
We hereby present a theoretical model that explains dynamical hysteresis in perovskite solar cells. It takes into account not only the specifications of the measurement but also the past history of the sample, expressed as an initial surface polarization voltage and charge, which yield a displacement current. The total current is then defined based on this current, a recombination current at the surface, and the photocurrent. The suggested model faithfully reproduces experimental data upon MAPI solar cells, and could be used as well to predict hysteretic effects in other perovskite-based solar cells.