"Beyond-DFT Studies for Thiophene and Furan Oligomers"

Autores: Vinicius Alves Bastos, Tales José da Silva, Marília Junqueira Caldas

Instituições: Universidade de São Paulo

Autor apresentador: Vinicius Alves Bastos

Resumo: Combined Thiophene and Furan oligomers are an emerging class of pi-conjugated materials, relevant in particular for optoelectronic applications. Indeed structures formed by these materials can show enhanced properties [1], combining qualities of both systems. In this work, we compare properties of dimers of Thiophene (2T), Furan (2F) and Thiophene-Furan (Thienylfuran/TF), basic units to form more complex copolymers. We study structural and electronic properties adopting ab-initio calculations including many-body GW corrections on top of hybrid DFT+HF [2,3]. In terms of structural results we find that 2T adopts a non planar antiparallel configuration (as well known), however 2F and TF tend to be antiparallel but planar, as a consequence of the atomic effective repulsion sulfur-hydrogen and attraction oxygen-hydrogen in the molecules. We find that the HOMO charge distribution for 2T, 2F and TF are very similar, justifying the similar Ionization Potential values seen in the experimental results [4], and confirmed by our GW results. These similarities apply also to the LUMO states. We will discuss also the optical properties [5], which include other occupied and unoccupied states, focusing mostly on the TF molecule.

[1] A. E. Steen et al., J. Phys. Chem. C, 123, 15176 (2019); [2] M. Pinheiro Jr et al., Phys. Rev. B, 92, 195134 (2015); [3] V. Blum et al., Comput. Phys. Commun., 180, 2175 (2009); [4] I. Novak et al., J. Electron Spectrosc., 61, 177 (1992); [5] C. Liu et al., J. Chem. Phys. 152, 044105 (2020).

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