Charge Transport Properties of Anthracene Derivatives

Abstract

The molecular geometries, electronic structures, reorganization energies, and charge transfer integrals of three anthracene derivatives {2,6-bis[2-(4-pentylphenyl)vinyl]anthracene, DPPVAnt; 2,6-bis-thiophene anthracene, DTAnt; 2,6-bis[2-hexylthiophene]anthracene, DHTAnt} were investigated by density functional theory at the B3LYP/ 6-31G(d) level. Their mobilities at room temperature were estimated using Einstein relations and compared with the calculated mobility of anthracene. DPPVAnt is a good hole-transporting material with a hole mobility as high as 0.49 cm2·V-1·s-1; DHTAnt is an electron-transporting material with an electron mobility of about 0.12 cm2·V-1·s-1; DTAnt is a bipolar material with its hole and electron mobilities being 0.069 and 0.060 cm2·V-1·s-1, respectively. The calculated mobilities were of the same magnitude as those obtained by experimental measurements. The reorganization energies for the electrons of the three derivatives are almost the same as that for anthracene but the reorganization energies for the holes of the three derivatives are larger than that of anthracene and they follow the order: anthracene DPPVAntDTAntDHTAnt. This is not in agreement with the order of the calculated mobilities and implies that the mobilities are determined by molecular packing.