Ab Initio Molecular Dynamics Assessment on the Mixed Ionic-Electronic Transport for Crystalline Poly(3-Hexylthiophene) Using Full Explicit Lithium-Based Dopants and Additives
D Mombru and M Romero and R Faccio and AW Mombru, MACROMOLECULES (2021).
Here, we report ab initio molecular dynamics calculations dealing with mixed ionic-electronic transport in a poly(3-hexylthiophene) crystalline supercell, including the use of full explicit lithium-based dopants and additives. Up to now and to the best of our knowledge, the use of full explicit dopants and additives for both ionic and electronic transport calculations has remained practically unexplored probably due to their high computational cost. The use of fewer artifacts and other common assumptions in our calculations allowed us to reveal some interesting behavior associated with the presence of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) dopants and dimethoxyethane (DME) additives on the mixed ionic-electronic transport in a wide temperature range. Our ionic and electronic conductivity calculations show a good correlation with the experimental reports of similar mixed ionic-electronic conductors in the very recent literature. For the electronic transport, our transfer integral (J) and reorientation energies (lambda) values showed increment respect to typical unexplicit- doped calculations. Furthermore, we also introduce the role of the explicit dopant in the interchain, intrachain, "effective" doping, and charge-transfer complex bonding distances, and their associated static and dynamic disorder effects on electronic transport. These new insights can be extremely helpful to unravel not only the doping mechanism but also, and simultaneously, the mixed ionic-electronic transport mechanism for organic semiconductors. Advancing in the fundamental understanding of mixed ionic-electronic organic conductors is a key to boosting their properties for different applications going from energy storage to bioelectronic devices.
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