Impact of Residual Lead Iodide on Photophysical Properties of Lead Triiodide Perovskite Solar Cells. Issue 3 (27th November 2019)

• Record Type: Journal Article
• Authors: Khan, Jafar I.; Sheikh, Arif D.; Alamoudi, Maha A.; Barrit, Dounya; Ugur, Esma; Laquai, Frédéric; Amassian, Aram
• Is Part Of: Energy technology. Volume 8:Issue 3(2020:Mar.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-11-27
• Subjects: charge carrier recombination -- interfacial recombination -- lead iodide -- perovskites -- spectroscopy; Energy development -- Periodicals; Power resources -- Periodicals; 333.79
• DOI: 10.1002/ente.201900627
• Languages: English
• ISSNs: 2194-4288

Abstract

Abstract : 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. Abstract : Moderate amount of residual lead iodide is beneficial for perovskite solar cells as shown by transient absorption spectroscopy. More specifically, photoexcitation from the perovskite/titanium dioxide (TiO2 ) side shows retarded charge carrier recombination at the interface.