The photophysical properties and electronic structures of bis[1]benzothieno[6,7-d:6',7'-d']benzo[1,2-b:4,5-b']dithiophene (BBTBDT) derivatives as hole-transporting for organic light-emitting diodes (OLEDs)

摘要： By using the quantum methods DFT and TD-DFT in this paper, the optoelectronic properties and electronic structures of eight compounds Ci (i=1-8) based on bis[1]benzothieno[6,7-d:6',7'-d']benzo[1,2-b:4,5-b']dithiophene (BBTBDT) with D-π-D structure for Ci (i=1-5); and D-π-A for Ci (i=6-8) have been calculated and discussed theoretically in the aim to consider them as hole-transporting materials (HTM) in OLEDs. The calculated electronic levels by B3LYP of studied compounds show that the proper energy of Ci (i=6-8) is so matching for efficiency injecting into hole-injection layer (HIL). The compounds having D-π-A structure seem more efficient than those having D-π-D structure. The optoelectronic properties for studied compounds obtained by TD-CAM-B3LYP elucidate that C6, C7 and C8 compounds behave as electron donating molecules and induce charge transfer character in the UV-visible absorptions and emission electronic spectra. Furthermore, the calculated reorganization energies, ionization potential (IP) and electron affinity (EA) also provide that the extended C6, C7 and C8 compounds have the highest charge-transporting ability among all compounds. It is found that the D-π-A more influence on the electronic and optoelectronic properties than the D-π-D structure. The assumed compound C7 is found to be a good candidate for blue-emitting material. Understanding these properties is important to design HTMs with exceptional properties, such as stability and high efficiency.