Eco-Compatible Solvent-Processed Organic Photovoltaic Cells with Over 16% Efficiency

Area of Science:

• Materials Science
• Organic Electronics
• Renewable Energy

Background:

• Nonfullerene acceptors (NFAs) have driven significant increases in organic photovoltaic (OPV) power conversion efficiencies (PCEs).
• Current high-efficiency OPVs rely on toxic solvents, hindering scalable manufacturing and commercialization.
• Developing OPV materials with good processability in eco-compatible solvents is crucial for widespread adoption.

Purpose of the Study:

• To design and synthesize novel NFA materials with improved processability in environmentally benign solvents.
• To achieve high PCEs in OPV devices fabricated using greener processing methods.
• To demonstrate the feasibility of large-area OPV production with eco-compatible solvents.

Main Methods:

• Modification of the flexible alkyl chains of the NFA BTP-4F-8 (Y6) to synthesize BTP-4F-12.
• Fabrication of OPV devices using BTP-4F-12 combined with polymer donors PBDB-TF and T1.
• Evaluation of device performance (PCE) and processability using various eco-compatible solvents and blade-coating techniques.

Main Results:

• The synthesized BTP-4F-12 achieved a PCE of 16.4% when paired with the polymer donor PBDB-TF.
• When using the more soluble polymer donor T1, OPV cells could be fabricated with various eco-compatible solvents.
• Blade-coated OPV cells (1.07 cm²) processed with tetrahydrofuran (THF) achieved over 14% efficiency.

Conclusions:

• Simple side-chain modification of NFAs can effectively tune the processability of active layer materials.
• The developed BTP-4F-12 demonstrates potential for high-performance OPVs fabricated using environmentally friendly solvents.
• This approach facilitates the mass production and commercialization of OPVs using scalable, greener methods.