Enhancement of electronic, photophysical and optical properties of 5,5 '-Dibromo-2,2 '-bithiophene molecule: new aspect to molecular design

Abstract

The aims of this study were to enhance electronic, photophysical and optical properties of molecular semiconductors. For this purpose, the isomers of the B-doped molecule (5,5'-Dibromo-2,2'-bithiophene) have been investigated by density functional theory (DFT) based on B3LYP/6-311++G** level of theory. The isomers were first calculated using kick algorithm. The most stable isomers of the B-doped molecule are presented depending on the binding energy, fragmentation energy, ionization potential, electron affinity, chemical hardness, refractive index, radial distribution function and HOMO-LUMO energy gap based on DFT. Ultraviolet-visible (UV-vis) spectra have been also researched by time-dependent (TD) DFT calculations. The value of a band gap for isomer with the lowest total energy decreases from 4.20 to 3.47 eV while the maximum peaks of the absorbance and emission increase from 292 to 324 nm and 392 to 440 nm with boron doped into 5,5'-Dibromo-2,2'-bithiophene. Obtained results reveal that the B-doped molecule has more desirable optoelectronic properties than the pure molecule. (C) 2019 Association of Polish Electrical Engineers (SEP). Published by Elsevier B.V. All rights