ИСТИНА

Ongoing materials research for organic electronics faces a problem of an enormously large exploration space, which to some extent can be solved by multiscale modeling. In particular, combining computational methods on several scales makes it possible to extract such key mesoscale properties of organic polymers as charge-carrier mobility, including the account for polaronic effects and/or disorder, and to relate them to morphology of bulk materials. We develop efficient methods for modeling of various conjugated polymer systems, from single chains to pi stacks, polymer bundles, and crystals. The developed methods are then applied to studies of organic cathode materials, solar cells, and field-effect transistors. On the materials side, we examine morphology and electronic properties of polymers shown in Fig. 1, as well as other systems of interest. To model structural properties, we use classical molecular dynamics with OPLS-type force field. The missing parameters are obtained from DFT calculations. The force field is tested on separate chains and bundles; the results are then compared to MM3 and DFT calculations. The adjusted force field is used to compute morphological structures of molecular crystals and polymer bundles. Electronic properties of structures thus simulated are computed using a localized molecular orbital approach, which allows to reduce the complexity of quantum chemical calculations to a tight-binding level while preserving a DFT-level accuracy.