Self‐assembled monolayers for perovskite solar cells

In metal‐halide perovskite solar cells (PSCs), various carrier recombination losses occur at the interface between metal oxides (MOs) and perovskite (PVK) due to the imperfect lattice structure of the crystal surface. Additionally, the nonoptimal energy levels of MOs and PVK, as well as ion diffusion and chemical corrosion between the two materials, severely hinder carrier transport at the interface. Therefore, there is an urgent need to introduce multifunctional materials between MOs and PVK to mitigate interface defects, carrier transport limitations, chemical corrosion, and other related issues. In recent years, self‐assembled monolayers (SAMs) have emerged as essential organic interfacial materials for effectively bridging MOs and PVK, playing a pivotal role in enhancing cells’ performance. Based on this, we provide a detailed overview of the origin and development of SAMs in PSCs and summarize the importance and potential of SAMs from various aspects, including their chemical structure, interface passivation, energy level tuning, and interface corrosion. We finally discuss the prospects of SAMs in terms of molecular structure, deposition methods, and their application in narrow‐band gap PSCs. With these insights, it is anticipated that SAMs will assist in realizing larger, highly efficient, stable, and cost‐effective PSCs, thereby enhancing the competitiveness of PSCs in the solar photovoltaics market.