Tuning of optoelectronic and charge transport properties in star shaped anthracenothiophene-pyrimidine derivatives as multifunctional materials

With the aim to tune the optoelectronic, charge transport and nonlinear optical properties, four novel star shaped compounds were designed from the initial structure 4,6-di(anthracenothiophen-2-yl)pyrimidine (DATP). The (2,5-di-(thiophen-2-yl)-4,6-di-(anthracenothiophen-2-yl)pyrimidine) (1), (2,5-di(benzo-thiophen-2-yl)-4,6-di-(anthracenothiophen-2-yl)pyrimidine) (2), 2,5-di(naphthothiophen-2-yl)-4,6-di-(anthracene-thiophen-2-yl)-pyrimidine (3), and 2,4,5,6-tetrakis(anthracene-thiophen-2-yl)pyrimidine (4) were deliberated by substituting the thiophene, benzothiophene, naphthothiophene and anthracenothiophene moieties at positions 2 and 5 of the pyrimidine unit in DATP, respectively. The ground and excited state geometries were optimized by adopting the density functional theory (DFT) and time-dependent DFT at B3LYP/6-31G** and TD-B3LYP/6-31G** level of theories, respectively. We shed light on the energies of the frontier molecular orbitals (FMOs), energy gaps (Egaps), absorption, fluorescence, total/partial density of states (T/PDOS), molecular electrostatic potentials (MEP) and non-linear optical (NLO) properties. The comprehensible intra-molecular charge transport has been noticed from side wings to the electron-deficient central core at both the ground and excited states. The increment in the wings length increases the electron affinity, reduces the ionization potential and lowered the hole reorganization energy. The higher electron affinity and smaller hole reorganization energy values revealed that newly designed materials might be thermodynamically more stable with enhanced intrinsic hole mobility.