Abstract by: Carlo Motta

Modeling Charge Transport on Organic Crystals

Organic semiconductors are attractive compounds for a growing range of applications such as sensors, displays, photovoltaics and integrated smart systems, owing to their low-cost processability and ecological sustainability. Finding efficient materials and optimizing the device design are tasks that can be rationalized with the benefit from computational modeling. In this context, a theoretical framework must be capable of describing the properties of the molecular crystal and of its interface with the metallic electrodes. Besides, it should be able to deal with different length scales. In this talk, I will present the work done in this field by our group at Trinity College Dublin. The case of a prototypical organic crystal, namely durene, will be presented. Wannier functions are shown to be useful for mapping the electronic structure information obtained by the microscopic calculation to a coarse-grained Hamiltonian [1]. Such a multiscale method enables the calculation of the charge carrier mobility at different temperatures, by either a mean-field [1] or a Monte Carlo [2] approach. Finally, a method to compute charge transfer energies for a molecule-metal interface will be shown [3].

As a side note, I will briefly touch on the topic of transitioning from academia to industry in the light of my recent experience.

References:

[1] C. Motta and S. Sanvito, “Charge Transport Properties of Durene Crystals from First-Principles” J. Chem. Theory Comput., 10, 4624-4632 (2014)

[2] R. Tiwari and S. Sanvito, “Modeling electronic transport in layered organic crystals”, Manuscript in preparation

[3] S. Roychoudhury, C. Motta, S. Sanvito "Charge transfer energies of benzene physisorbed on a graphene sheet from constrained density functional theory" Phys. Rev. B 93, 045130 (2016)