So-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.
%0 Journal Article
%1 ebadi2019origin
%A Ebadi, Firouzeh
%A Taghavinia, Nima
%A Mohammadpour, Raheleh
%A Hagfeldt, Anders
%A Tress, Wolfgang
%D 2019
%J Nature Communications
%K apparent capacitance enhanced light negative origin
%N 1
%P 1574--
%R 10.1038/s41467-019-09079-z
%T Origin of apparent light-enhanced and negative capacitance in perovskite solar cells
%U https://doi.org/10.1038/s41467-019-09079-z
%V 10
%X So-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.
@article{ebadi2019origin,
abstract = {So-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.},
added-at = {2019-04-10T13:56:43.000+0200},
author = {Ebadi, Firouzeh and Taghavinia, Nima and Mohammadpour, Raheleh and Hagfeldt, Anders and Tress, Wolfgang},
biburl = {https://www.bibsonomy.org/bibtex/2dd32e0f909bc5446fa3ede9b37c300e4/sere},
doi = {10.1038/s41467-019-09079-z},
interhash = {12332bb5f04d5e6e0599a51a562ce371},
intrahash = {dd32e0f909bc5446fa3ede9b37c300e4},
issn = {20411723},
journal = {Nature Communications},
keywords = {apparent capacitance enhanced light negative origin},
number = 1,
pages = {1574--},
refid = {Ebadi2019},
timestamp = {2019-04-10T13:56:43.000+0200},
title = {Origin of apparent light-enhanced and negative capacitance in perovskite solar cells},
url = {https://doi.org/10.1038/s41467-019-09079-z},
volume = 10,
year = 2019
}