Hi everybody, As I mentioned on Friday, we will have a special group meeting tomorrow (Tuesday) at 2pm in the Division Room. Our speaker is Jarvist Frost from the group of Jenny Nelson at Imperial College London. Please find the title and abstract of his talk below. We still have meeting slots with Jarvist before his seminar, so please let me know asap if you want to meet with him. Cheers Johannes ###################################################### Computational Design of Materials for Organic Photovoltaics Jarvist Moore Frost, Samuel Foster, Jenny Nelson Imperial College London, London, United Kingdom. Designing higher efficiency and more stable organic solar cells will require new materials. Computational chemistry offers the opportunity for large combinatorial sifts through potential structures without the time and expense of physical synthesis. We have developed heavily automated methods based on electronic structure calculations to probe the material parameters that control charge dynamics in these materials. In order to study charge transport in the weak coupling limit we calculate electronic transfer integrals explicitly for representative molecular assemblies generated by atomistic molecular modelling. We study the inner sphere reorganisation energies of relevant existing and hypothesised molecules, including heterocycles, non-benzenoid aromatics and non-fullerene acceptors to identify areas of possible future synthesis.We treat energetic disorder by combining a molecular dynamics approach with a tight-binding model for some classical conjugated polymers, generating densities of stateswhich can be compared with experiment. These studies indicate that torsional freedom of the backbone is the dominant source of energetic disorder. In order to study photo-excited states and the mechanism of charge separation, Singlet and Triplet excited states are investigated with Time-Dependent (TD) Density Functional Theory (DFT) and compared to transient absorption data for newly synthesised push-pull polymers. We then apply Generalized Kohn-Sham (GKS) DFT with the ab-initio tuned BNL meta-hybrid range-separated functional to probe the nature of charge generation at the Donor-Acceptor (DA) interface in the organic solar cell and the role of the charge transfer state. The self-consistent tuning of the functional allows us to go correct for failings in standard hybrid functionals which are particularly important in charge-transferring systems such as the DA interface. We apply our results in suggesting rules for the rational choice of chemical structure in the synthesis of new materials. ----------------------------------------------- Dr. Johannes Hachmann Research Associate Aspuru-Guzik Research Group Harvard University Department of Chemistry and Chemical Biology 12 Oxford St, Rm M104A Cambridge, MA 02138 USA eMail: jh(a)chemistry.harvard.edu ----------------------------------------------- _______________________________________________ Aspuru-meetings-list mailing list Aspuru-meetings-list(a)lists.fas.harvard.edu https://lists.fas.harvard.edu/mailman/listinfo/aspuru-meetings-list