Premium
Decoupling of Implied and External V OC Due to Ionic Movement Explaining Transient V OC Overshoot in Perovskite Solar Cells
Author(s) -
Herterich Jan,
Unmüssig Moritz,
Wagner Lukas,
Loukeris Georgios,
Faisst Jared,
List Mathias,
Kohlstädt Markus,
Würfel Uli
Publication year - 2022
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.202100868
Subject(s) - decoupling (probability) , perovskite (structure) , overshoot (microwave communication) , ionic bonding , photoluminescence , transient (computer programming) , materials science , analytical chemistry (journal) , voltage , open circuit voltage , chemistry , atomic physics , condensed matter physics , physics , optoelectronics , molecular physics , ion , electrical engineering , crystallography , organic chemistry , chromatography , quantum mechanics , control engineering , computer science , engineering , operating system
An overshoot of the open‐circuit voltage ( V OC ) after switching off the illumination is observed for perovskite solar cells, while the simultaneously measured photoluminescence (PL) intensity decreases continuously. Similarly, a dip in the photovoltage transient is detected at the beginning of a light pulse added to a continuous bias light, while the PL increases. This decoupling of external and implied V OC (as derived from the PL data) originates from a strong gradient of the majority charge carrier quasi‐Fermi level in the vicinity of a nonideal contact. This gradient reduces the external voltage much more than the implied voltage. The V OC overshoot is observed whenever the gradient decreases faster than when the separation of the quasi‐Fermi levels is reduced by charge carrier recombination. As shown in previous work, in perovskite solar cells, the magnitude of the gradient is strongly influenced by mobile ionic species and it decreases upon light soaking. This is why a fully light‐soaked device does not show this kind of V OC overshoot.