Optimization of active layers for efficient binary organic solar cells

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cell (OSC) performance is critically dependent on the active layer's microstructure.
• Optimizing morphology requires coordinated control over preparation parameters.

Purpose of the Study:

• To systematically investigate the impact of preparation parameters on OSC active layer morphology and performance.
• To identify optimal conditions for enhancing exciton dynamics, charge transport, and light absorption.

Main Methods:

• Utilized the PM6:L8-BO active system for organic solar cells.
• Studied the effects of annealing temperature, film thickness, and solvent additives (e.g., diiodooctane - DIO).
• Analyzed film microstructure, exciton behavior, charge transport, phase separation, and light absorption.

Main Results:

• An annealing temperature of 90 °C and DIO as a solvent additive were found to optimize active layer micromorphology.
• Achieved a champion power conversion efficiency (PCE) of 18.33% for binary OSCs.
• Specific device parameters included an open-circuit voltage (Voc) of 0.881 V, short-circuit current density (Jsc) of 26.56 mA cm⁻², and fill factor (FF) of 78.33%.

Conclusions:

• Coordinated control of preparation parameters is crucial for high-performance organic solar cells.
• Optimal processing conditions, specifically annealing temperature and solvent additives, significantly boost device efficiency.
• The study demonstrates a pathway to achieving high PCEs in organic solar cells through morphological control.