Theoretical Studies by Using the DFT and TD-DFT of the effect of the bridge formed of thienopyrazine in solar cells

To understand the effect of the bridge part in organic solar cells,in the first we have done the synthesis of two compounds for objective to predict experimentally theirs properties optoelectronics and to comparing theses properties with those obtained by different functional ( b3lyp,camb3lyp,pbepbe,b3pw91) therefore to find the appropriate quantum method for reproducing the optoelectronics properties,in the second part we have made theoretical studies of six compounds of thienopyrazine derivatives,by using dft/b3lyp/6-31 g(d,p) level for optimize the geometry structures and predict the electronics properties. the time-dependent dft (td-dft/cam-b3lyp /6-31g(d,p)) level has been used for predict the excitations properties. this study includes the predicting of the energy of homo and lumo level,the gap energy,the voc (open circuit voltage) and λmax of absorption and other quantum parameters. the result shows that the performance of solar cells favors better with increasing the π conjugated of the bridge.