Construction of a long range p/n heterojunction with a pair of nanometre-wide continuous D/A phases

Abstract

A p/n heterojunction is the basic setup for light-electric conversion. It has been widely accepted that the ideal configuration for organic photovoltaics is formed by the joint of a pair of long-range continuous but nanometre-wide phases consisting of electron-donating (D) and -accepting (A) components, respectively. Such a p/n heterojunction can provide not only a large D/A interface essential to efficient photoinduced charge separation, but also the transportation pathways for both electrons and holes. This review article summarizes the present approaches including D–A double cables, diblock copolymers, and small molecular D–A dyads and multiads, to construct such an ideal p/n heterojunction. Each approach is introduced by a few selected representative works, with highlights on their molecular design strategies and the relationship of chemical structure–packing order–property. Such information would be useful for the next research in the field.