Conjugated polymers (CPs) have proven to be useful materials in organic photovoltaic (OPV) devices. Polythiophenes are particularly interesting CPs due to the tunable nature of their electronic structures and their relative environmental stability. In this computational study, 91 diversely substituted thiophene monomers were combined into 4095 unique dimer pairs. These dimers were used to construct alternating (AB)<sub>n</sub> oligomers (4095 tetramers, 110 hexamers, and 60 octamers). DFT-B3LYP/6-31G(d) geometry optimizations were performed and the HOMO and LUMO energies were extracted for each of these 8451 chemical structures. Infinite polymer HOMO, LUMO, and HUMO/LUMO gap (E<sub>g</sub>) energies were extrapolated for the 60 AB combinations for which hexamer and octamer calculations had been performed. Statistical models were developed to relate monomer and small oligomer electronic properties to the extrapolated polymer energies. It was found that monomer data alone was not sufficient to predict the extrapolated electronic energies of the infinite polymers using our statistical models. The inclusion of tetramer and dimer data into these models provided a significant increase in robustness of their predictive power.

Predicting polythiophene electronic structures: Statistical model screening for the efficient discovery of OPV materials

253rd National Meeting (2017)

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