Molecular Stacking and Aggregation Optimization of Photoactive Layer through Solid Additive Enables High-Performance...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Optimizing molecular packing and aggregation in the photoactive layer is crucial for high-performance organic solar cells.
• Controlling π-stacking significantly impacts charge transport and device efficiency.

Purpose of the Study:

• To investigate the effects of anthra[2,3-b:6,7-b\]dithiophene (ADT) and naphtho[1,2-b:5,6-b\]dithiophene (NDT) as solid additives on the molecular arrangement of organic solar cell photoactive layers.
• To enhance the photovoltaic performance and stability of organic solar cells through controlled molecular aggregation.

Main Methods:

• Synthesis and characterization of ADT and NDT analogues.
• Fabrication of organic solar cells using these additives.
• Analysis of molecular packing, π-stacking, and photovoltaic performance.

Main Results:

• NDT promotes face-on stacking of Y6 and ordered π-π stacking, improving film morphology.
• ADT induces a mix of face-on and edge-on stacking due to its herringbone arrangement and non-volatility.
• NDT treatment significantly improved power conversion efficiency (PCE), reaching 18.85% in a PM6:L8-BO device, compared to 16.41% for the control.

Conclusions:

• ADT and NDT serve as effective solid additives for regulating molecular packing and aggregation in organic solar cells.
• NDT demonstrates a particularly promising strategy for enhancing photovoltaic performance through improved molecular ordering.
• This approach offers a viable route to achieving higher efficiency and stability in organic solar cell devices.