Selectively Modulating the Donor and Acceptor Aggregation Behaviors Through Solid Additive Isomerization Engineering...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• High-performance organic solar cells (OSCs) require precise control over film morphology.
• Solid additives offer a promising strategy to selectively manage donor and acceptor material aggregation.

Purpose of the Study:

• To design and investigate bithiophene isomer solid additives (2,2-TT, 2,3-TT, 3,3-TT) for regulating organic solar cell film morphology.
• To understand how additive structure influences the aggregation behavior of donor and acceptor materials.

Main Methods:

• Synthesis of 2,2-TT, 2,3-TT, and 3,3-TT bithiophene isomers.
• Fabrication and characterization of organic solar cells using these additives.
• Analysis of film morphology, molecular packing, and photovoltaic performance.

Main Results:

• The 3,3-TT additive effectively promoted compact and ordered molecular packing of both donor (PM6, D18) and acceptor (L8-BO) materials.
• PM6:L8-BO based OSCs treated with 3,3-TT achieved 19.34% efficiency due to balanced charge mobility and longer carrier lifetime.
• D18:L8-BO based OSCs with 3,3-TT treatment reached a remarkable 20.32% efficiency with an excellent 82.47% fill factor.

Conclusions:

• Solid additive isomerization is a critical strategy for selectively controlling donor and acceptor aggregation in OSCs.
• The 3,3-TT additive significantly enhances organic solar cell performance by optimizing film morphology.
• This approach paves the way for further advancements in high-efficiency organic solar cell technology.