Staggering increases in the performance of organic–inorganic perovskite solar cells have renewed the interest in these materials. However, further developments and the support from academic and industrial partners will hinge on the reporting of accurate efficiency values.
As pointed out by Grätzel, some open issues and pitfalls are now being debated in this community. Among these, the main concern revolves around the accuracy of the reported efficiency values. Specifically, hysteretic behaviour due to the strong dependence of the photocurrent on the voltage-scan conditions seems to be particularly pronounced in some perovskite solar cells. This has led to doubts about some reported power-conversion efficiency values, which may be altered by hysteresis-related artefacts.