Radical approach to modeling electron conducting polymers

The promise of organic electron-conducting polymers creates outstanding opportunities for flexible, low-cost, and sustainable optoelectronics and energy storage devices. An emerging class of electron-conducting polymers is non-conjugated radical-containing polymers (RAPs). These are organic polymers with a non-conjugated backbone and pendant-stable radical sites. RAPs successfully transport charges without relying on π-conjugation, instead using redox reactions between the pendant radical groups. This introduces a new paradigm in polymer-based electron transport. However, our understanding of these materials is incomplete and the molecular mechanisms underpinning their properties remain elusive. In E-RADICAL, I will advance our understanding of RAPs through the development of a novel multiscale modeling approach that combines molecular dynamics, quantum dynamical methods, and machine learning. This approach will enable, for the first time, quantum-dynamically accurate and computationally efficient simulations of charge transport in realistic, disordered RAP morphologies. The proposed multiscale approach will be used to perform a comparative study of charge transport in highly conductive RAPs and conjugated polymers, extracting underlying principles governing efficient charge transport. Finally, I will generate the first computational condensed-phase library of RAPs, allowing me to deduce structure-property relationships and formulate design guidelines for this emerging class of materials. In summary, E-RADICAL will provide detailed and unprecedented understanding of the molecular mechanisms driving charge transport in RAPs, thereby informing the rational design of improved materials with ramifications for the development of devices that enable a future with clean and affordable energy.