3,6‐Bis(methylthio)‐9<i>H</i>‐carbazole Based Self‐Assembled Monolayer for Highly Efficient and Stable Inverted Perovskite Solar Cells
Shahid Ameen, Dongmin Lee, Abdullah Bin Faheem, Jung Geon Son, Youngwan Lee, Hyunjoon Yoo, Sujung Park, Yun Seop Shin, Jaehwi Lee, Jongdeuk Seo, Hyungsu Jang, Jina Roe, Ji Won Song, Shinuk Cho, Yongsup Park, Kyung‐Koo Lee, Kyung‐Koo Lee, Jin Young Kim, Jin Young Kim, Dong Suk Kim, Dong Suk Kim, BongSoo Kim
Abstract
Abstract The photovoltaic performance of inverted perovskite solar cells (PSCs) relies on effectively managing the interface between the hole extraction layer and the light‐absorbing perovskite layer. In this study, we have synthesised (4‐(3,6‐bis(methylthio)‐9 H ‐carbazol‐9‐yl)butyl)phosphonic acid (MeS‐4PACz), which forms a self‐assembled monolayer (SAM) on the fluorine‐doped tin oxide (FTO) electrode. The molecule‘s methylthio substituents generate a favourable interfacial dipole moment and interact with the perovskite layer. This interaction results in well‐aligned energy levels among the FTO/SAM/perovskite layers, promoting efficient hole extraction and significantly reducing carrier recombination losses. Additionally, the methylthio groups passivate iodide vacancies and interact with Pb 2+ ions of the perovskite, reducing defect‐induced trap states and enhancing the crystalline growth of the perovskite layer. Consequently, inverted PSCs incorporating MeS‐4PACz achieve a power conversion efficiency of 25.13 %, along with outstanding photostability.