Theoretical Study of the Electronic and Optical Properties to Design Dye-Sensitivity for Using in Solar Cell Device

In this work, the structural and optoelectronic properties of phenanthrene-1,3,4-thaidiazoles oligomers were calculated using density functional theory (DFT) at B3LYP/6-31G(d) basis set level, to evaluate their possible application as organic semiconductor materials in photovoltaic and solar cell devices. For this reason, the energy gaps, frontier orbital (HOMO, and LUMO) distributions, total energies, Fermi level energies, work functions and maximum wavelength absorption, vertical absorption energies, and oscillator strengths have been investigated and discussed. The structures of phenanthrene-1,3,4-thiadiazoles oligomers are expanded from 1 to 10 thiadiazole monomeric units, to examine the increase of thiadiazole monomeric units on the optoelectronic properties. We observed that increased the number of monomeric units lead to significantly enhance the optoelectronic properties, which caused to decrease the gap energy from 3.69 eV in the structure with one thiadiazole ring just to 2.36 eV with 10 units. These changes give the shift of maximum absorption wavelengths from 376 to 578 nm. Consequently, these molecules have main absorption bands within the solar spectrum, to give the best performance for photovoltaic and organic solar cells devices.