Exploring the electronic, optical and charge transfer properties of acene-based organic semiconductor materials.

In order to tune the optoelectronic and charge transfer properties of 4,6-di(thiophen-2-yl)pyrimidine (1), some new compounds were designed, i.e., 4,6-bis(benzo[b]thiophen-2-yl)pyrimidine (2), 4,6-bis(naphtho[2,3-b]thiophen-2-yl)pyrimidine (3), 4,6-bis(anthra[2,3-b]thiophen-2-yl)pyrimidine (4), 4,6-bis(tetraceno[2,3-b]thiophen-2-yl)pyrimidine (5) and 4,6-bis(pentaceno[2,3-b]thiophen-2-yl)pyrimidine (6). Compounds 2–6 were designed by assimilation of benzene, naphthalene, anthracene, tetracene and pentacene, respectively at both ends of compound 1. Integration of oligocene end cores reduces the energy gap resulting in a red shift in the absorption and fluorescence emission spectra. The legible intra-molecular charge transfer is significant from electron-rich moieties to the electron-deficient core (pyrimidine). The elongation of π -conjugation led to escalate the electron affinity, lower the ionization potential and hole reorganization energy. The hole reorganization energies of compounds 3–6 exposed that these materials would be effective hole transport contenders to be used in diverse semiconductor devices. [ABSTRACT FROM AUTHOR]