A Top-Down Strategy to Engineer ActiveLayer Morphology for Highly Efficient and Stable All-Polymer Solar Cells

Area of Science:

• Materials Science
• Polymer Chemistry
• Renewable Energy

Background:

• All-polymer solar cells (all-PSCs) face challenges in active-layer morphology control, impacting fill factor (FF).
• Issues stem from phase separation and disordered polymer chain orientation in blends of macromolecular acceptors.

Purpose of the Study:

• To develop a facile top-down strategy for engineering all-polymer blend morphology.
• To improve fill factor and overall efficiency in all-polymer solar cells.

Main Methods:

• Utilized layer-by-layer (LBL) deposition for controlled morphology.
• Tuned bottom-layer polymer swelling and top-layer solvent for optimal intermixing and molecular ordering.
• Fabricated all-PSCs using the developed LBL processing protocol.

Main Results:

• Achieved optimal intermixing and molecular orientation/packing in the active layer.
• Realized a favorable morphology with gradient vertical composition for efficient charge transport.
• Obtained a high all-PSC efficiency of 17.0% with a fill factor of 76.1%.

Conclusions:

• The LBL deposition strategy effectively engineers all-polymer blend morphology.
• This method leads to high-performance all-PSCs with excellent efficiency and stability.
• The developed protocol offers distinct advantages for fabricating high-performance all-PSCs.