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Impact of Residual Lead Iodide on Photophysical Properties of Lead Triiodide Perovskite Solar Cells
Author(s) -
Khan Jafar I.,
Sheikh Arif D.,
Alamoudi Maha A.,
Barrit Dounya,
Ugur Esma,
Laquai Frédéric,
Amassian Aram
Publication year - 2020
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.201900627
Subject(s) - iodide , perovskite (structure) , triiodide , materials science , lead (geology) , perovskite solar cell , titanium dioxide , solar cell , chemistry , inorganic chemistry , chemical engineering , dye sensitized solar cell , optoelectronics , metallurgy , crystallography , engineering , electrode , geomorphology , electrolyte , geology
The role of residual lead iodide on the photophysical properties of methylammonium lead iodide is still unclear and contradictory views exist about its impact. Herein, it is reported that there is a critical amount of residual lead iodide, which is beneficial for the solar cell performance. Transient absorption spectroscopy is used to investigate the charge carrier recombination dynamics in perovskite solar cells and to address the role of different amounts of residual lead iodide. The amount of lead iodide is varied through the perovskite thin film preparation protocol upon a modified two‐step fabrication process. Slower carrier dynamics are observed at the perovskite/titanium dioxide interface in the presence of residual lead iodide when exciting the perovskite at the perovskite/titanium interface, which correlates with improved solar cell device performance. Excitation from the perovskite side indicates that the effect of residual lead iodide is primarily at the titanium dioxide interface. Increasing the lead iodide content does not further alter the carrier recombination; on the contrary, it results in lower device performance. This study confirms that the presence of lead iodide can have a beneficial effect, as it reduces charge carrier recombination at the perovskite/titanium dioxide interface.