Synthesis and Optoelectronic Applications of d(& pi;)-p(& pi;) Conjugated Polymers with a Di-metallaaromatic Acceptor

The development of conjugated polymers especially n-type polymer semiconductors is powered by the design and synthesis of electron-deficient building blocks. Herein, a strong acceptor building block with di-metallaaromatic structure was designed and synthesized by connecting two electron-deficient metallaaromatic units through a & pi;-conjugated bridge. Then, a double-monomer polymerization methodology was developed for inserting it into conjugated polymer scaffolds to yield metallopolymers. The isolated well-defined model oligomers indicated polymer structures. Kinetic studies based on nuclear magnetic resonance and ultraviolet-visible spectroscopies shed light on the polymerization process. Interestingly, the resulted metallopolymers with d(& pi;)-p(& pi;) conjugations are very promising electron transport layer materials which can boost photovoltaic performance of an organic solar cell, with power conversion efficiency up to 18.28 % based on the PM6 : EH-HD-4F non-fullerene system. This work not only provides a facile route to construct metallaaromatic conjugated polymers with various functional groups, but also discovers their potential applications for the first time.

Automated summary

In this study, a strong acceptor building block with a di-metallaaromatic structure was designed and synthesized, and then inserted into conjugated polymer scaffolds through a double-monomer polymerization methodology to yield metallopolymers. Kinetic studies using nuclear magnetic resonance and ultraviolet-visible spectroscopies provided insights into the polymerization process. The resulting metallopolymers with d(& pi;)-p(& pi;) conjugations showed promising electron transport properties and significantly enhanced photovoltaic performance in an organic solar cell.