Top Electrode‐Assisted Hole‐Transporting Layer Deposition for Perovskite Solar Cells

The incorporation of hole‐transporting material (HTM) is crucial for optimizing the photovoltaic performance of perovskite solar cells (PSCs). However, the standard spin‐coating method commonly used in laboratories is not conducive to the large‐scale preparation of HTMs for devices. In this study, we present a novel approach that employs conductive porous overlayers, specifically multi‐walled carbon nanotube (MWCNT) films, to facilitate the fabrication of HTM layers. By integrating MWCNT films with HTM precursor solutions, we achieved the simultaneous formation of the HTM layer and the top electrode. Furthermore, selecting an appropriate additional cover layer allowed us to create an HTM layer characterized by uniform thickness and optimal contact with the MWCNT‐based electrode. This innovative method eliminates the need for specialized equipment and enables PSC devices to achieve a power conversion efficiency of 17.58% with good stability. This streamlined approach holds significant promise for enabling large‐scale, cost‐effective production of high‐performance perovskite solar cells while addressing the challenges associated with conventional HTM preparation techniques.