Oligoether‐Chain‐Enriched Self‐Assembled Molecules With High Dielectric Constant for Co‐Deposition of Efficient Perovskite Solar Cells

Abstract Although self‐assembled molecules (SAMs) have shown great potential in simplifying the fabrication of perovskite solar cells (PSCs) as the co‐deposited hole‐selective layers (HSLs), only a few SAMs have demonstrated high device performance up to date. In this work, a series of novel SAMs with a phosphonic acid group directly anchored onto the carbazole skeleton is designed. This linking mode can prevent the aggregation of SAMs in the solution state while enhancing their photostability. By further incorporating oligoether side chains, the target SAMs EGCPA and 3EGCPA can form homogeneous and dense HSL during the co‐deposition process and assist the growth of high‐quality perovskite film. Particularly, 3EGCPA featuring multiple oligoether chains possesses a high dielectric constant, which enables more efficient interfacial hole extraction and transfer, thereby reducing the charge recombination. Consequently, the 3EGCPA‐based co‐deposited PSCs delivered a champion efficiency of 24.64% along with good ISOS‐D‐1 stability, which is among the highest performances for co‐deposited PSCs. Furthermore, acoustic resonance can be effectively utilized to test the power conversion efficiency (PCE) of PSCs. This work provides a creative molecular design strategy for exploring efficient hole‐selective molecules with a high dielectric constant applied in PSCs.