Subphthalocyanine Triimides: Solution Processable Bowl-Shaped Acceptors for Bulk Heterojunction Solar Cells

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Subphthalocyanine derivatives are explored for organic electronics.
• Developing efficient non-fullerene acceptors is crucial for organic solar cells.

Purpose of the Study:

• To design and synthesize novel subphthalocyanine triimides (SubPcTI) as electron acceptors.
• To investigate their electronic and optical properties.
• To evaluate their performance in organic solar cells.

Main Methods:

• Synthesis of ten SubPcTI compounds with varied substituents.
• Characterization of their lowest unoccupied molecular orbital (LUMO) energy levels and absorption spectra.
• Fabrication and testing of non-fullerene bulk heterojunction organic solar cells.

Main Results:

• Synthesized SubPcTI compounds exhibit low-lying LUMO levels (-3.91 to -3.98 eV).
• Compounds show strong absorption in the 450-650 nm range and tunable solubility.
• Organic solar cells utilizing acceptor 8c achieved a power conversion efficiency of 4.92%.

Conclusions:

• The designed SubPcTI derivatives are promising electron acceptors for organic solar cells.
• The achieved efficiency represents a record for subphthalocyanine-based solar cells.
• Further optimization could lead to even higher performance photovoltaic devices.