Article_Ilies_TAIBI.pdf

A series of five new promising π-conjugated compounds was designed to investigate thiophene based organic materials with enhanced optoelectronic properties for photovoltaic applications. This theoretical study employs two distinct computational approaches to determine the most effective method for analyzing the electronic properties of these compounds. Density functional theory (DFT) calculations, using both B3LYP and the Perdew-Burke-Ernzerhof (PBE) functionals under vacuum and one dimensional periodic boundary conditions (PBC-1D) respectively, combined with 6-31G(d,p) basis set, were performed to optimize molecular structures, analyze frontier molecular orbitals (FMOs), and calculate electronic parameters such as gap energy and open circuit voltage (Voc), using PC61BM as the electron acceptor. In addition, time-dependent density functional theory (TD-DFT) with the B3LYP functional in the same basis set was used to determine key optical properties, including the absorption spectra, maximum wavelength (λmax) and excitation energy.<br>Our theoretical and computational study revealed that these newly designed π-conjugated thiophene based compounds show promising optoelectronic properties, indicating potential for enhancing the efficiency of organic photovoltaic devices. Furthermore, this work emphasizes the reliability of the PBE functional under periodic boundary conditions as an effective approach for studying the electronic properties of such materials, offering an enhanced methodology for future research on efficient organic photovoltaic compounds.