Interfacial toughening with self-assembled monolayers enhances perovskite solar cell reliability

Tougher solar cell interfaces The low formation energies of the active layers in perovskite solar cells lead to low-toughness materials that are compliant and soft, which limits their interface stability and long-term reliability. Dai et al. show that treatment with iodine-terminated self-assembled monolayers that react with surface hydroxyl groups (which ultimately creates unwanted charge traps and voids) leads to a 50% increase of adhesion toughness between the electron transport layer and a mixed-composition perovskite thin film. The projected point at which 80% of the operating efficiency in perovskite solar cells was still retained increased from ∼700 to 4000 hours for 1-sun exposure with continuous maximum power point tracking. Science , this issue p. 618