DFT study of small compounds based on thiophene and benzo[1,2,5] thiadiazole for solar cells: Correlation-structure / electronic properties

In this work,we report theoretical analysis on the geometries and optoelectronic properties of new small conjugated compounds based on quaterthiophene and benzo[1,2,5]thiadiazole as acceptor,these compounds were designed and studied by using density functional theory (dft) and time-dependent (td) calculations. the study of the structural and optoelectronic properties (homo,lumo,gap energy,voc) is realized by using dft method at becke's three parameters and lee- yang-parr functional (b3lyp) level with 6-31g(d) basis set. the calculations were performed by gaussian 09 program supported by gauss view 5.0.8 the effects of the electron-donating groups (oh,och3 and ch3) and electron-withdrawing groups (cl,br,cn and cho) substituents on the geometries,electronic and photophysical properties of these molecules are discussed to investigate the relationship between structure and optoelectronic properties. these properties suggest these materials as good candidates as active layer for organic solar cells. © 2017,university of mohammed premier oujda morocco.