Long-term efficient organic photovoltaics based on quaternary bulk heterojunctions

Area of Science:

• Materials Science
• Energy Science
• Organic Electronics

Background:

• Commercialization of organic photovoltaics (OPVs) is hindered by the poor morphological stability of the bulk heterojunction (BHJ) layer.
• Multi-component BHJ systems offer a strategy to balance performance and stability in OPVs.

Purpose of the Study:

• To develop high-efficiency and long-term durable OPVs using quaternary BHJs (q-BHJs).
• To investigate the stability enhancement mechanism in q-BHJ OPVs.

Main Methods:

• Fabrication of quaternary BHJ OPVs (q-OPVs) using two conjugated polymer donors and two fullerene acceptors.
• Experimental optimization of q-OPV composition.
• Performance and operational lifetime testing of q-OPVs compared to binary BHJ OPVs at elevated temperatures (65°C).

Main Results:

• The optimized q-OPV demonstrated enhanced efficiency and extended operational lifetime compared to binary OPVs.
• The q-OPV retained over 72% of its initial efficiency after one year of operation at 65°C.
• Superior long-term stability was observed compared to state-of-the-art BHJ-based OPVs.

Conclusions:

• Quaternary BHJs provide a promising platform for developing highly efficient and durable OPVs.
• Enhanced stability is attributed to the suppression of domain growth and phase separation through kinetic trapping.