Keywords :
Benzothiadiazoles; Charge carriers transport; Conjugated backbones; Conjugated copolymers; Donor/acceptor; First principle calculations; Model Hamiltonians; Nonadiabatic molecular dynamics; Parameterized; Thermally activated; Physics and Astronomy (all); Physical and Theoretical Chemistry; General Physics and Astronomy
Abstract :
[en] Disordered or even seemingly amorphous, donor-acceptor type, conjugated copolymers with high charge-carrier mobility have emerged as a new class of functional materials, where transport along the conjugated backbone is key. Here, we report on non-adiabatic molecular dynamics simulations of charge-carrier transport along chains of poly (indacenodithiophene-co-benzothiadiazole), within a model Hamiltonian parameterized against first-principles calculations. We predict thermally activated charge transport associated with a slightly twisted ground-state conformation, on par with experimental results. Our results also demonstrate that the energy mismatch between the hole on the donor vs the acceptor units of the copolymer drives localization of the charge carriers and limits the intra-chain charge-carrier mobility. We predict that room-temperature mobility values in excess of 10 cm2 V-1 s-1 can be achieved through proper chemical tuning of the component monomer units.
Funding text :
We acknowledge Dr. Yoann Olivier (University of Namur, Belgium) and Dr. Vincent Lemaur for useful discussions and suggestions. Computational resources have been provided by the Consortium des Équipements de Calcul Intensif (CÉCI), funded by the Fonds de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under Grant No. 2.5020.11 and by the Walloon Region. This research also benefited from the computational resources made available on the Tier-1 supercomputer of the Fédération Wallonie-Bruxelles infrastructure funded by the Walloon Region under Grant Agreement No. 1117545. This work was financially supported by the FNRS FLAG-ERA JTC 2017 project “MXene-organic semiconductor blends for high-mobility printed organic electronic devices—MX-OSMOPED.” D.B. is a FNRS Research Director. L.W. acknowledges support from the National Natural Science Foundation of China (Grant Nos. 21873080 and 21922305).
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