Design of organic/polymeric π-semiconductors: The four-element principle

Organic semiconductors are charge carrier-transporting molecular solids with π-orbital channels. Organic semiconductors are π-systems that can be created via the molecular engineering of π-orbitals. In this review, we present a pattern in physical organic chemistry by summarizing four fundamental elements of organic/polymeric π- semiconductors according to our previous work. These include electronic structure, steric hindrance, conformation and topology, and supramolecular interactions. Advances in the field of organic/polymeric π-semiconductors with respect to these four elements are highlighted to demonstrate the impact on device functionality and performance. We also provide an outlook of the four-element principle as a basic thinking pattern in scientific research.