Backbone orientation in semiconducting polymers

Charge carrier transport is one of the most important functions of semiconducting polymers when they are used in organic electronic devices. Due to the transport path limited in two directions, i.e., along the π-conjugated backbone and intermolecular π-π stacking, the backbones are required to be oriented in the desired motifs with respect to the substrate, such as "edge-on" and "face-on" in order to maximize the device performances. In this Feature Article, we focus on how the orientation of semiconducting polymer backbones are influenced by the chemical structure, e.g., backbone structure, molecular weight, and side chains, and processing conditions. Implications of the backbone orientation for the performance of organic devices such as transistors and solar cells are also discussed.