Additive-Induced Vertical Component Distribution Enables High-Performance Sequentially Cast Organic Solar Cells.

Area of Science:

• Materials Science
• Organic Electronics
• Renewable Energy

Background:

• Optimizing active layer morphology is crucial for enhancing organic solar cell (OSC) efficiency.
• Vertical component distribution structures are key to improving OSC performance.
• Precise morphological control is essential for high-performance OSC fabrication.

Purpose of the Study:

• To investigate the effect of additive strategies on active layer morphology in OSCs.
• To achieve precise control over morphology using a layer-by-layer (LbL) spin-coating method.
• To enhance the power conversion efficiency (PCE) of D18-Cl/Y6 based OSCs.

Main Methods:

• Employed a layer-by-layer (LbL) spin-coating technique.
• Utilized an additive strategy, incorporating n-octane and 1-fluoronaphthalene (FN).
• Fabricated and characterized OSCs based on the D18-Cl/Y6 system with and without additives.

Main Results:

• Single additive treatments (n-octane or FN) improved PCE to 17.70% and 17.39%, respectively, compared to control devices (16.66%).
• n-octane promoted orderly D18-Cl arrangement and suitable phase separation.
• FN enhanced Y6 crystallization, facilitating carrier transport.
• Dual-additive treated devices (D18-Cl+/Y6+) achieved a notable PCE of 18.16%, with improved Jsc (27.17 mA cm-2) and FF (76.88%).

Conclusions:

• Combining LbL spin-coating with additive strategies enables hierarchical morphology control in OSCs.
• This approach significantly enhances device performance, achieving high power conversion efficiencies.
• The findings are highly significant for the fabrication and development of advanced OSCs.