Monodisperse Co-oligomer Approach toward Nanostructured Films with Alternating Donor-Acceptor Lamellae

摘要

Limited by short exciton diffusion length (～10 nm) of organic semiconductors, nanostructured films with electron-donor (D) and electron-acceptor (A) bicontinuous phases with nanometer-scale interspacing for efficient charge separation and transport are highly desirable for preparation of high-performance polymer solar cells (PSCs). PSCs are usually fabricated with blends of D and A materials, and it is rather difficult to realize the aforementioned film morphology. Block copolymers intrinsically prefer composition-dependent nanophase separation due to the incompatibility between different blocks. Accordingly, several D-A block copolymers with fullerene or perylene diimide (PDI) as the A component have been prepared for achieving nanostructured D-A heterojunctions. However, due to the polydispersity and rigid nature of conjugated polymers, disordered naonostructures with domain sizes larger than 20 nm were often obtained. Consequently, the efficiencies of the resulting PSCs were lower than 0.5%, and design and synthesis of materials toward well-defined nanostructured D-A heterojunctions remain great challenges.