Ebadi, FirouzehTaghavinia, NimaMohammadpour, RahelehHagfeldt, AndersTress, Wolfgang2019-06-182019-06-182019-06-182019-04-0510.1038/s41467-019-09079-zhttps://infoscience.epfl.ch/handle/20.500.14299/157064WOS:000463472200019So-called negative capacitance seems to remain an obscure feature in the analysis of the frequency-dependent impedance of perovskite solar cells. It belongs to one of the puzzling peculiarities arising from the mixed ionic-electronic conductivity of this class of semiconductor. Here we show that apparently high capacitances in general (positive and negative) are not related to any capacitive feature in the sense of a corresponding charge accumulation. Instead, they are a natural consequence of slow transients mainly in forward current of the diode upon ion displacement when changing voltage. The transient current leads to a positive or negative 'capacitance' dependent on the sign of its gradient. The 'capacitance' appears so large because the associated resistance, when thinking of a resistor-capacitor element, results from another physical process, namely modified electronic charge injection and transport. Observable for a variety of devices, it is a rather universal phenomenon related to the hysteresis in the current-voltage curve.Multidisciplinary SciencesScience & Technology - Other Topicssurface polarizationinductive looprecombinationhysteresisvoltageperformanceefficiencystatesmodeltext::journal::journal article::research article