  We investigate in how far the hysteresis-free behavior of perovskite solar
cells can be reproduced using particular pre-conditioning and measurement
conditions. As there are currently more and more reports of perovskite solar
cells without J-V hysteresis it is crucial to distinguish between genuine
performance improvements and measurement artifacts. We focus on two of the
parameters that influence the dynamic J-V scans, namely the bias scan rate and
and the bias poling voltage, and point out measurement conditions for achieving
a hysteresis-free behavior. In this context we discuss the suitability of
defining a hysteresis index (HI) for the characterization of dynamic J-V scans.
Using HI, aging effects are also investigated, establishing a potential
connection between the sample degradation and the variation of the maximal
hysteresis on one hand, and relaxation time scale of the slow process, on the
other hand. Pre-poling induced recombinations effects are identified. In
addition, our analysis based on sample pre-biasing reveals potential indication
regarding two types of slow processes, with two different relaxation time
scales, which provides further insight regarding ionic migration.
