Conjugation break spacers and flexible linkers as tools to engineer the properties of semiconducting polymers

Developing tools to understand and control the effect of semiconducting polymer morphology on the optoelectronic performance remains an important objective. Introducing conjugation break spacers (i.e., flexible linkers) between pi-conjugated segments in a semiconducting polymer is an emerging strategy toward this goal. Herein, we place this strategy in context with other extrinsic and intrinsic engineering approaches and highlight some of the recent results employing this flexible linker approach. We see that the inclusion of electrically insulating aliphatic spacers represents a versatile tool to gain insight into the nature of inter-molecular and intra-molecular charge carrier transport and can be broadly used to control morphology of solution-processed semiconducting polymer thin films. Moreover, this approach has afforded unique control over material processing and mechanical properties (e.g., viscosity and elasticity) without detrimental effect on the semiconducting ability. While the development of this technique remains at an early stage, its potential gives promise to reaching the goal of engineering the self-assembly of semiconducting polymers.