Simulations of Structure-Property Relationship of Nanomaterials: Amorphous Conjugated Polymers

Nanotechnology represents a nexus of materials science, chemistry, physics, and engineering and is vital for the development of revolutionary applications ranging from electronics and photovoltaics to medicine. However, before advances in next generation technologies can come to fruition, understanding and control of the structure-property relationship of nanomaterials are required. Theoretical predictions based on atomistic modeling could provide valuable insight into these issues. In this talk, I first briefly overview various quantum-chemical approaches that we use for description of the morphology, optoelectronic properties, and photo-excited dynamics in novel nano-structured energy materials, such as quantum dots, carbon nanotubes, and conjugated polymers. Next, the talk will be focused on studies of localization and transport properties in amorphous conjugated polymers. We have modeled the conformational inter- and intra-molecular disorder and analyzed its impact on the electronic structure of amorphous poly-p-phenylene vinylene (PPV) and poly-(9,9)-di-oxtylfluorene (PFO). We found that hole-traps originate from inter-molecular interactions, while electron-traps stem from intra-molecular disorder. These results open a new prospective for understanding of disorder in amorphous organic semiconductors - the key knowledge to improve efficiency of organic optoelectronic devices.