Pei Jian's research group in the School of Chemistry Prog. Polym. SCI Review: Solution aggregation state regulation of conjugated polymers

The macroscopic photoelectric function of conjugated polymers is closely related to its microscopic multi-level assembly structure at different spatial scales, including chemical structure, conformational distribution, intermolecular interaction, chain arrangement, crystallization behavior, film morphology and other structural characteristics
.
Precise regulation of molecular assembly structure is of great scientific significance for the development of high-performance conjugated polymers, but the multi-level and complex microstructure of conjugated polymers makes it extremely challenging
to characterize and regulate their assembly structure.
Incomplete and missing information on the microstructure of conjugated polymers makes it difficult to construct a clear "structure?" Performance relationship
.

Figure 1.
Multi-stage assembly structure of conjugated polymers at different spatial scales and common characterization methods

For the complex multi-level assembly structure of conjugated polymers, Professor Pei Jian's research group from the School of Chemistry and Molecular Engineering of Peking University has long been committed to achieving precise regulation of polymer multi-level assembly structure through molecular structure design, polymer solution and crystallization regulation, and proposed the quaternary assembly structure of conjugated polymer for the first time (Chinese Journal of Polymers, 2019, 50, 1-12).

In view of the in-depth research in this field, Pei Jian was recently invited to work in the top journal Prog.
Polym.
An important review
of aggregation state regulation strategies in conjugated polymer solutions was published in SCI.

Figure 2.
Aggregation state regulation strategy of conjugated polymer solution

Starting from the interaction between conjugated polymer chains and solvent molecules, this review analyzes the formation mechanism of conjugated polymers from solution to thin film, elaborates the important roles of molecular structure, solvent engineering, temperature, aggregation kinetics and molecular accumulation, systematically summarizes the methods for regulating the solution assembly structure and crystallization behavior of conjugated polymers, and elaborates the relationship between the multi-level assembly structure of conjugated polymers and the charge transport mechanism, especially the importance of
solution aggregation state regulation strategy 。 On the basis of clarifying the complex multi-level assembly structure of conjugated polymers, a clear "molecular structure?" is established.
Assemble the structure? The structure-activity relationship of "device performance", in-depth understanding of the aggregation behavior and multi-level assembly structure of conjugated polymer solution, can more accurately regulate the morphology and microstructure of polymer films, and provide a theoretical basis and optimization strategy
for the application of high-performance conjugated polymers and their applications in functional devices such as field effect transistors, solar cells, and organic thermoelectrics.

Figure 3.
The central role of the aggregate state of the conjugated polymer solution

The first author of the work is Yao Zefan, a doctoral student in the School of Chemical and Molecular Engineering, and the corresponding author is Pei Jian
.
The work has been funded and supported
by the National Natural Science Foundation of China, the Ministry of Science and Technology, the Beijing Municipal Education Commission, and the Beijing National Research Center for Molecular Sciences.

Link to paper: