Computational Design and Characterisation of Organic Mixed Conductors

This talk will give an overview of the current research activities in the group, ranging from de novo design and screening of mixed ionic-electronic conductors to computational testing of novel side chain designs using molecular dynamics (MD) simulations.

Sustainable and environmentally benign organic mixed conductors are necessary for applications such as edible, implantable or transient electronics. Bioinspired building blocks have not yet been systematically included in computational design/screening efforts that have become commonplace in organic electronics. In this work, we introduce a computational funnel approach for the high-throughput screening of bioinspired organic mixed conductors. We present the validation of our screening approach using indole (eumelanin-inspired) units as a proof-of-concept, and we propose a series of novel promising structures characterised by a donor-acceptor design and low reorganisation energy.

The OMIEC design space has been mostly dominated by conjugated polymers with glycol side chains, with very limited effort towards the design of different polar side chain motifs. However, side chain engineering can fundamentally change key properties such as hydrophilicity, polarity, crystallinity/order, as well as carrier mobility in conjugated polymers. MD simulations offer a tool to investigate trends in side chain engineering through 'controlled in silico experiments', avoiding confounding variables and nonlinearities that often characterise experimental trends in different polymer families.
In this work, the influence of the side chain structure on the properties of a seried of naphthalene diimide (NDI) polymers was systematically investigated by varying the side chains of the NDI units. MD simulations of polymer aggregates in the presence of different electrolytes were used to assess the ability of each side chain motif to mediate ion-polymer interactions and π-stacking.