| 초록 |
One of approaches to improve polymer solar cells is to employ new conjugated polymers with low band-gap and appropriate energy levels of the highest/lowest molecular orbital (HOMO/LUMO). One strategy to obtain such low band-gap polymers is to synthesize alternating copolymers by combining appropriate electron-rich monomers with electron-poor monomers. Dialkoxynaphthalene is planar, and can form an intermolecular π-π stacking, leading to a high charge mobility. On the other hand, diketopyrrolo[3,4-c]pyrrole (DPP) is a very strong acceptor that can lower the HOMO level. Thieno[3,4-c]pyrrole-4,6-dione (TPD) is also a strong acceptor. In this study, two alternating copolymers consisting of dialkoxynaphthalene and DPP or TPD with a thiophene spacer were synthesized. This study indicated that alkoxy substisuents on naphthalene moieties can lower the HOMO levels, but the resulting polymers' band-gap can become larger. |
