DFT and TD-DFT study on the optical and electronic properties of derivatives of 1,4-bis(2-substituted-1,3,4-oxadiazole)benzene

Abstract

A series of 1,4-bis(2-substituted-1,3,4-oxadiazole)benzene derivatives has been designed to explore their optical, electronic, and charge transport properties for luminescent and charge transport materials. The frontier molecular orbitals (FMOs) analysis have turned out that the vertical electronic transitions of absorption and emission are characterized as intramolecular charge transfer (ICT). Both λabs and λfl of the derivatives with 2-thiophene and 2-1H-pyrrole fragments show bathochromic shifts compared with parent compound 2-pyridyl substituted derivative (1), while the corresponding values of the substituted derivatives with 4-pyridyl, 2-pyrazine, and phenyl fragments are similar to those of parent compound 1. Our results suggest that the substituted derivatives with 4-pyridyl, 2-pyrazine, phenyl, 2-thiophene, and 2-1H-pyrrole fragments are expected to be promising candidates for luminescent materials for OLEDs. Furthermore, the substituted derivatives with 4-pyridyl, 2-pyrazine, phenyl, and 2-thiophene fragments can be used as promising electron transport materials, while the substituted derivatives with 2-pyrazine and 2-1H-pyrrole fragments can be used as promising hole transport materials. In addition, the substituted derivative with 2-pyrazine fragment may be used as good candidate for ambipolar charge transport material for OLEDs.

Keywords

• 1,4-Bis(2-substituted-1,3,4-oxadiazole)benzene
• Organic light-emitting diodes (OLEDs)
• Absorption spectra
• Fluorescence spectra
• Reorganization energy