Modeling of photoactive conjugated donor–acceptor copolymers: the effect of the exact HF exchange in DFT functionals on geometries and gap energies of oligomer and periodic models

Abstract

Conjugated copolymers with an alternating donor-acceptor (D-A) architecture are exploited as low-bandgap and high-hole-mobility materials in organic electronics. However, several of the presently available modeling methods predict different geometries and electronic properties for the same copolymer. In this work, the effect of the amount of exact Hartree-Fock (HF) exchange in density functionals on the planarity of the geometry and the electronic properties of the single oligomer chains of one benzodithiophene- and benzotriazole-based donor-acceptor copolymer and two fluorene-, thiophene-, and benzotriazole-based donor-acceptor copolymers is assessed. The functionals are B3LYP, PBE, PBE0, HSE06, LC-ωPBE, ωB97XD, M06, M06L, M062X, M06HF, and the optimally tuned OT-ωB97X. Benchmarking of the methods is useful for understanding the results of a particular functional and allows, to a certain degree, comparison between results obtained with different functionals. Additionally, the applicability of the one-dimensional periodic boundary condition (PBC) for modeling the D-A copolymers with long constitutional repeating units (CRUs) is evaluated.

Effective conjugation in conjugated polymers with strongly twisted backbones: a case study on fluorinated MEHPPV

“…1b, as well as Fig. 39 Nevertheless, it should be reminded that fluorine not only induces geometrical distortions when placed in sterical demanding positions like in the current case. 39 Nevertheless, it should be reminded that fluorine not only induces geometrical distortions when placed in sterical demanding positions like in the current case.…”

Molecular Reactivity and Absorption Properties of Melanoidin Blue-G1 through Conceptual DFT

“…Various TDDFT studies of different sizes of molecules have used the optimally-tuned RSH density functionals. The studies report that absorption properties improve especially when applying the charge-transfer phenomenon [ 51 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 ].…”

Electronic couplings and rates of excited state charge transfer processes at poly(thiophene-co-quinoxaline)–PC71BM interfaces: two- versus multi-state treatments

“…53 Tuning of o in the LRC functionals is known to improve the calculated excitation energies of D-A copolymers with respect to the experimental ones. [63][64][65][66] Moreover, the FCD scheme has been reported to yield electronic couplings of stacked small molecules (i.e. ethylene, pyrrole, and naphthalene) closer to the experimental Mulliken-Hush values, when the OT version of the LRC Baer-Neuhauser-Livshits (BNL) 67,68 functional (incorporating the full 100% HF exchange into the LR component) has been used.…”