Flexible All-Solution-Processed Organic Solar Cells with High-Performance Nonfullerene Active Layers

Area of Science:

• Materials Science
• Energy Science
• Organic Electronics

Background:

• All-solution-processed organic solar cells are desired for low-cost applications but face challenges with nonfullerene active layers.
• Key issues include poor charge extraction and wetting problems at the interface between the active layer and the top electrode (PEDOT:PSS).

Purpose of the Study:

• To enhance the efficiency of all-solution-processed nonfullerene organic solar cells.
• To address charge extraction and wetting challenges at the active layer/PEDOT:PSS interface.

Main Methods:

• Incorporation of a hydrogen molybdenum bronze (HₓMoO₃) layer between the nonfullerene active layer and the PEDOT:PSS top electrode.
• Careful synthesis of HₓMoO₃ to control its composition and ensure processing orthogonality.

Main Results:

• The HₓMoO₃ layer demonstrated dual functionality: effective hole extraction due to its deep Fermi level (-5.44 eV) and improved wetting of PEDOT:PSS.
• Achieved power conversion efficiencies of 11.9% for small-area (0.04 cm²) and 10.3% for large-area (1 cm²) flexible cells.

Conclusions:

• Hydrogen molybdenum bronze is a critical interfacial layer for efficient all-solution-processed nonfullerene organic solar cells.
• Controlled synthesis of HₓMoO₃ enables processing compatibility and improved device performance.