A multiscale computational tool for the study of morphology and charge transport properties of heterointerfaces in organic electronic devices

The development of advanced and multi-functional materials for organic and hybrid electronic and optoelectronic devices is often hampered by the lack of a detailed understanding of property/structure relationship, and especially of the link between molecular structure, nanoscale aggregation and electronic properties. This issue affects particularly interfaces among molecular layers in devices based on thin-film architecture, where the chemico-physical complexity of the system leads to difficult interpretation of experimental results. In this regard, computational investigations can shed light on the relationship between the morphology at the interfaces and the electronic properties of the materials constituting the organic layers. In this work, we present the computational tool MIRTO (Modeller of Interfaces and chaRge injection raTes calculatOr). MIRTO represents an integrated multiscale approach able to model the aggregation of organic materials, in realistic environments, at the interface with organic and inorganic substrates, applying Molecular Dynamics (MD) simulations. In addition, the morphologies obtained are used to investigate the electronic phenomena occurring at the interface by performing Density Functional Theory (DFT) calculations. This framework provides distributions of structural parameters and charge injection rates, enabling the correlation between nanoscale morphologies and charge transport properties in materials constituting the layers of organic devices. In particular, this tool was applied to two different cases. Namely, morphologies at the interface between a metal and an organic semiconductor were used to compute charge injection rates. Also, we investigated the aggregation of an organic n-type semiconducting material at the interface with graphene. The approach developed within MIRTO, integrated with experimental validation and characterization, allows the correlation between nanoscale morphology of materials at heterointerfaces, dynamical phenomena and electronic properties, leading to a multiscale computational tool that can be applied to the development and design of advanced materials and devices.