Chlorine-mediated organic conjugated materials and quasi-planar heterojunction devices

The properties of organic functional materials are determined by both their chain structure and the intermolecular interactions. Based on the basic concept of precisely controlling intermolecular interactions, we have developed a series of material systems with specific transport structures by controlling the arrangement and aggregation of organic optoelectronic molecules through the Cl∙∙∙S and Cl∙∙∙π interactions. In particular, we discovered a three-dimensional (3D) network structure in the model molecules with specific chlorine-mediated intermolecular interactions. We also systematically studied the effects of chlorine substitution position, number, and isomerism on the formation of the 3D network structure, which could provide the better molecular design strategy to achieve improved device performance. With the exciton diffusion distance exceeding 40 nm, those materials open a window for the development of quasi-planar heterojunction (Q-PHJ) devices. Compared with bulk heterojunction (BHJ) devices, Q-PHJ devices have a thermodynamically stable donor-acceptor bilayer structure, which can greatly improve device stability for coming practical applications.