Inverted bulk-heterojunction solar cell with cross-linked hole-blocking layer

Area of Science:

• Materials Science
• Renewable Energy
• Organic Electronics

Background:

• Bulk-heterojunction solar cells require efficient charge transport layers.
• Polyethylenimine (PEI) is a promising material for hole-blocking layers.
• Improving the stability and reproducibility of these layers is crucial for commercialization.

Purpose of the Study:

• To develop and evaluate a cross-linked polyethylenimine (PEI) based hole-blocking layer for bulk-heterojunction solar cells.
• To investigate the impact of cross-linking on PEI layer properties and solar cell performance.
• To assess the solvent resistance and reproducibility of the cross-linked PEI layer.

Main Methods:

• Synthesis of cross-linked PEI using five different ether-based cross-linkers.
• Fabrication of bulk-heterojunction solar cells incorporating the cross-linked PEI layer.
• Characterization of solar cell efficiency and device reproducibility.
• Evaluation of PEI layer adhesion and solvent resistance.

Main Results:

• All tested cross-linkers yielded comparable solar cell efficiencies.
• The cross-linked PEI layer demonstrated excellent adhesion to indium-tin-oxide electrodes, unaffected by processing solvents.
• The cross-linked PEI layer functioned effectively with various donor-acceptor blends.
• Cross-linking significantly improved the reproducibility of the solar cell fabrication process.

Conclusions:

• Cross-linked PEI serves as an effective hole-blocking layer in bulk-heterojunction solar cells.
• While not enhancing solvent resistance, cross-linking improves device fabrication consistency.
• The developed cross-linked PEI layer offers a viable solution for reproducible organic solar cell manufacturing.