Anti-Naphthalene Bisbenzimidazole Columnar Mesogens as Interfacial Modifiers in Perovskite Solar Cells

Abstract

Introducing the interfacial layer is a strategic way to improve the performances and stability of perovskite solar cells by optimizing charge transport, reducing recombination, and proper energy level alignment. In conventional perovskite solar cells, the commonly used hole transport layer, Spiro-OMeTAD, is limited by its poor hole mobility, low intrinsic conductivity and susceptibility, which result to interfacial defects and device degradation. To address these challenges, we developed organically self-assembled semiconductor utilizing anti-naphthalene bisbenzimidazole (NB20) as interfacial layer between perovskite and Spiro-OMeTAD.NB20 layer enhances hole extraction, passivate the interfacial defects, and improves charge transport, leading to an approximately 9% performance boost through better energy level alignment and lower recombination losses. Additionally, the modified device with passivated layer shows enhanced stability by maintaining 80.69% of original power conversion efficiency after 1000 hours, whereas unmodified devices have retained only 58.73% of their initial performance