Merocyanine with Hole-Transporting Ability and Efficient Defect Passivation Effect for Perovskite Solar Cells

Development of charge-transporting molecules that can simultaneously passivate multiple surface defects of perovskites is highly desirable for further performance increase of perovskite solar cells (PVSCs). Herein, we describe a simple strategy for designing a passivation molecule with good hole mobility based on conjugated merocyanine dye. Remarkably, we reveal that merocyanine with zwitterionic resonance structure character in the ground state can efficiently passivate the deep-level defects such as lead/iodide vacancies and eliminate the negative effects of neutral iodine defects, leading to an effective reduction of charge recombination and a preferred band bending at the surface of the perovskite film for hole extraction. Therefore, a significant increase in power conversion efficiency (PCE) from 19.78% to 22.04% is achieved for the dye-treated conventional n-i-p PVSCs. Our work shows a new molecular platform for designing efficient defect passivation molecules for perovskites.

Automated summary

A simple strategy for designing passivation molecules with good hole mobility based on merocyanine dye has been proposed to increase the efficiency of perovskite solar cells. The study showed that merocyanine molecules with zwitterionic resonance structure can efficiently passivate multiple surface defects, reducing charge recombination and optimizing charge extraction efficiency.