Electronic States at the Interface between Crystalline and Amorphous Domains in Conjugated Polymers

Abstract

Conjugated polymers exhibit complex structure with interlaced crystalline and amorphous domains. We have investigated electronic structure of the interface between crystalline and amorphous domains in poly(3-hexylthiophene) (P3HT). Two types of the interface were considered: sharp interface and interface composed of extended chains. We have found that HOMO states of both interface types belong to the crystalline domains. States belonging to both domains were not found. We have calculated HOMO and LUMO band offsets between crystalline and amorphous domains. These offsets are close to previous estimates in the case of interface with extended chains. We find that there is no formation of trap states at the investigated interfaces. Regardless of the interface type, amorphous domains present high barriers for charge carriers, which lead to charge transport through crystalline domains.