MULTIXMAS

Guiding design of molecular materials for sustainable energy applications hinges on the understanding and control of excitation dynamics in functional nanostructures. Performance in, e.g., organic photovoltaics, photocatalysis, or soft thermoelectrics, is determined by multiple electronic processes, which emerge from interaction between electronic structure and nano- and mesoscale morphology. 

Resolving this intimate interplay is crucial but extremely difficult as it requires linking quantum and classical techniques in an accurate and predictive way. In MULTIXMAS, we will develop bottom-up simulations of charge/exciton dynamics in large-scale morphologies. 

Hierarchical multiscale structure equilibration of nanomaterial will be combined with excited state electronic structure theory based on Many-Body Green’s Functions, parameter-free electron-dynamics models, and kinetic Monte Carlo. Essential method development is accompanied by the technological challenge of high-performance and high-throughput computing. 

As a prototypical system, we study charge generation in low-cost organic photovoltaic cells (OPVCs) for which a breakthrough increase of power conversion efficiency (PCE) from currently ~11% to or above that of conventional silicon-based devices (20%) is required to play a significant role in meeting the growing demand for renewable energy. 

Our tools will provide a general framework for multiscale simulations of excitation dynamics in complex molecular systems, with relevance beyond energy-related applications.