17.1 %-Efficient Eco-Compatible Organic Solar Cells from a Dissymmetric 3D Network Acceptor

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Polymer solar cells (PSCs) offer a promising renewable energy solution.
• Developing efficient PSCs processed with environmentally friendly, non-halogenated solvents is crucial.
• Existing acceptor materials often face limitations in performance and stability.

Purpose of the Study:

• To design and synthesize a novel dissymmetric fused-ring acceptor, BTIC-2Cl-γCF3, for non-halogenated solvent-processed PSCs.
• To investigate the molecular packing, charge transport, and photovoltaic performance of the new acceptor.
• To achieve high power conversion efficiency (PCE) exceeding current benchmarks.

Main Methods:

• Chemical synthesis of the BTIC-2Cl-γCF3 acceptor molecule.
• X-ray crystallographic analysis to determine molecular packing structure.
• Fabrication and characterization of PSC devices using PBDB-TF as a donor and PC71ThBM as a third component.
• Performance evaluation including power conversion efficiency (PCE), stability, and optical properties.

Main Results:

• The synthesized BTIC-2Cl-γCF3 exhibits a 3D network packing structure, enhancing charge transport.
• Toluene-processed binary devices achieved a PCE of 16.31%, increasing to 17.12% with a ternary component.
• The new acceptor demonstrates excellent storage and photo-stability, with absorption extended to 852 nm.
• Achieved PCE over 17% represents the highest efficiency for PSCs processed with non-halogenated solvents.

Conclusions:

• The dissymmetric BTIC-2Cl-γCF3 acceptor effectively enhances PSC performance with non-halogenated solvents.
• Optimized molecular aggregation and charge transport contribute to the high efficiency.
• The material's stability and optical properties suggest potential for semi-transparent building-integrated photovoltaics (ST-BIPV).