How measurement protocols influence the dynamic J-V characteristics of perovskite solar cells: Theory and experiment

Abstract

The dynamic effects observed in the J-V measurements represent one important hallmark in the behavior of the perovskite solar cells. Proper measurement protocols (MPs) should be employed for the experimental data reproducibility, in particular for a reliable evaluation of the power conversion efficiency (PCE), as well as for a meaningful characterization of the type and magnitude of the hysteresis. We discuss here several MPs by comparing the experimental J-V characteristics with simulated ones using the dynamic electrical model (DEM). Pre-poling conditions and bias scan rate can have a dramatic influence not only on the apparent solar cell performance, but also on the hysteretic phenomena. Under certain measurement conditions, a hysteresis-free behavior with relatively high PCEs may be observed, although the J-V characteristics may be far away from the stationary case. Furthermore, forward-reverse and reverse-forward bias scans show qualitatively different behaviors regarding the type of the hysteresis, normal and inverted, depending on the bias pre-poling. We emphasize here that correlated double-scans, forward-reverse or reverseforward, where the second scan is conducted in the opposite sweep direction and begins immediately after the first scan is complete, are essential for a correct assessment of the dynamic hysteresis. In this context, we define a hysteresis index which consistently assigns the hysteresis type and magnitude. Our DEM simulations, supported by experimental data, provide further guidance for an efficient and accurate determination of the stationary J-V characteristics, showing that the type and magnitude of the dynamic hysteresis may be affected by unintentional pre-conditioning in typical experiments.

Hysteresis-less and stable perovskite solar cells with a self-assembled monolayer

“…It has been reported that one of the relevant origins of the inverted hysteresis is the ion migration in PSCs 9,27,28 . The migration of different ionic species in perovskite films could cause the J-V hysteresis, the degree of which depends on the voltage scan rates 9 , directions (forward-to-reverse or reverse-to-forward bias scans) 29 , ranges 27,30 , and temperature 31 . Thus, we measured J-V curves in the consecutive reverse-to-forward scans (Supplementary Fig.…”

Modification of NiOx hole transport layers with 4-bromobenzylphosphonic acid and its influence on the performance of lead halide perovskite solar cells

“…[52] which considers the integrated power output of the solar cells in fwd (SC to OC) and bwd (OC to SC) scan directions. Based on Nemnes et al [53][54][55] this method is useful for the determination of the HI for normal and inverted hysteresis in non-crossing JV curves. If the HI approaches 0, the solar cell would have negligible hysteresis.…”

Hysteresis Passivation in Planar Perovskite Solar Cells Utilizing Facile Chemical Vapor Deposition Process and PCBM Interlayer

“…Recently, Nemnes et al [33] investigated the influences of measurement techniques on the dynamic J-V performance, indicating that the extent and type of the J-V hysteresis were dramatically dependent on the pre-poling conditions and the bias scan rate. The "S" shaped J-V curves shown in Figure 7 were consistent with the findings in reference [33], if the perovskite solar cell was pre-poled at open-circuit, the forward scan curve present a crossover point with the following reverse scan curve. The overall PCE performances present here had no advantages compared to the excellent published work [34] due to the poor surface morphology and crystal quality of the perovskite films, on which our future work would focus.…”