ABSTRACT Conjugated self‐assembled monolayers (SAMs) have demonstrated significant advantages as hole‐transport layers (HTLs) in inverted perovskite solar cells (PSCs). Nevertheless, the crucial effect of SAMs’ conjugation skeletons and molecular orientation of exerting on the interfacial modification between perovskite and indium tin oxide (ITO) substrates remains inadequately understood. To address this issue, two representative bipodal SAMs with rigid indolo2,3‐ b carbazole (2IDPA) and flexible biscarbazole (2CzPA) as conjugation ends are carefully designed herein. Both theoretic simulation and experimental studies show 2IDPA contributes dense compact coverage and superior interfacial interaction for hole extraction/transport in PSCs. Featuring Edge‐on orientation, 2IDPA exhibits stronger adsorption on ITO surface to promote the crystallization and growth of perovskite films. A champion power conversion efficiency of 24.28% is readily afforded together with improved long‐time operation stability, outperforming the flexible dual‐anchoring 2CzPA (22.54%) and mono‐anchoring MeO‐4PACz workhorse SAMs (21.61%). The dual‐anchoring SAMs with designated molecular orientation strategy highlight a promising approach in the design of interfacial charge transport layers to advance the development of solution‐processable PSCs.
Huo et al. (Sun,) studied this question.