Asymmetric Non-Fullerene Acceptors with Different Halogen Terminal Groups for Effective Passivation in Highly...

Area of Science:

• Materials Science
• Renewable Energy
• Organic Electronics

Background:

• Interfacial issues in perovskite solar cells (PSCs) hinder efficiency and stability.
• Effective defect passivation is crucial for improving PSC performance.
• Asymmetric organic molecules are underexplored for defect passivation in PSCs.

Purpose of the Study:

• To investigate the impact of asymmetric organic molecules (SY1, SY2) and a symmetric molecule (Y6) as passivators in inverted PSCs.
• To correlate molecular structure with passivation effectiveness and device performance.
• To optimize perovskite layer properties for enhanced solar cell efficiency.

Main Methods:

• Synthesis and introduction of asymmetric (SY1, SY2) and symmetric (Y6) organic molecules.
• Characterization of perovskite film properties, including molecular orientation and crystallization.
• Fabrication and performance testing of inverted PSC devices.

Main Results:

• SY1, with its asymmetric structure and chlorine substitution, promoted face-on orientation and facilitated grain boundary passivation.
• SY1 demonstrated superior defect and grain boundary passivation compared to SY2 and Y6.
• SY1-based devices achieved a power conversion efficiency (PCE) of 25.63%, outperforming SY2 (24.12%) and Y6 (24.70%) devices.

Conclusions:

• Asymmetric molecular design is a promising strategy for developing effective passivators in PSCs.
• Molecular structure significantly influences perovskite film quality and device performance.
• SY1 represents a novel and effective passivator for high-efficiency inverted PSCs.