Exploring the effect of oligothiophene and acene cores on the optoelectronic properties and enhancing p- and n-type ability of semiconductor materials

Abstract

ABSTRACT We designed six 4,6-di(pentacenothiophene-2-yl)pyrimidine molecules with excellent charge transport properties. The optimization of ground-state geometries with B3LYP/6-31G** level is adopted with the help of first-principle investigations. The bridge elongation strategy was employed to strengthen intra-molecular charge transfer. The time-dependent density functional theory (TDDFT) was employed for the measurement of absorption spectra (λabs). The λabs, energy gaps (Egaps ), frontier molecular orbitals (FMOs) energies, electron injection, ionization energy (IE), electron affinity (EA) along with reorganization energy (λ) values were computed. The substitution of long-chain polyacene cores as well as thiophene enhanced the EA, reduces hole/electron λ along with their IE. The λ(h), and λ(e), were compared with hole and electron transfer within mostly used compounds, like pentacene and tris(8-hydroxyquinolinato)aluminum (mer-Alq3), respectively. It is anticipated that novel designed compounds may be better to be used for hole transfer (as pentacene) and electron transfer (as mer-Alq3) compounds. These derivatives would act as productive materials that can be employed as p- and n-type semiconductors. The elongation of oligothiophene and acene cores act as excellent hole transfer materials that may be better than frequently used p-type reference compounds. These designed derivative also showed lower values exhibited that these may be best/comparable with commonly used n-type mer-Alq3.