Small molecules based on benzo[1,2-b:4,5-b']dithiophene unit for high-performance solution-processed organic solar...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Small molecules are promising for organic solar cells due to tunable properties.
• Developing efficient and stable small-molecule donors is crucial for advancing solar cell technology.

Purpose of the Study:

• To design and synthesize novel small molecules for bulk heterojunction solar cells.
• To investigate the photovoltaic properties of these new molecules and their structure-performance relationships.

Main Methods:

• Synthesis of DCAO(3)TBDT and DR(3)TBDT small molecules.
• Fabrication of bulk heterojunction solar cells using these molecules as donors and fullerene derivatives as acceptors.
• Performance characterization under AM 1.5G irradiation (100 mW cm(-2)).

Main Results:

• DR(3)TBDT demonstrated excellent photovoltaic performance.
• A power conversion efficiency of 7.38% (certified 7.10%) was achieved for DR(3)TBDT-based solar cells.
• This represents the highest efficiency reported for small-molecule solar cells to date.

Conclusions:

• Fine-tuning molecular structure significantly impacts photovoltaic performance.
• Solution-processed small-molecule solar cells can achieve efficiencies comparable to or exceeding polymer-based counterparts.
• These findings highlight the potential of small molecules for high-performance, low-cost solar energy conversion.