Performance evaluation of PTB7: PC71BM based organic solar cells fabricated by spray coating method using chlorine free solvent

The PTB7 : PC71BM polymer based solar cells have been successfully fabricated by spin and spray coating technique using chlorine-free solvent (xylene), which are desirable to reduce environmental issues. The surface morphology of fabricated film characterized by AFM reveals that the surface morphology of the film is uniform and smooth when xylene is used as compared with chlorobenzene. The highest power conversion efficiency (PCE) (5.07 +/- 0.6) was achieved using spray-coating technique than that of spin coating technique (PCE of 4.47 +/- 0.6). The enhancement in the performance of the polymer solar cell could be attributed to the improved charge carrier transportation due to additive. The combination of chlorine-free solvent and spray-coating method minimize the waste material and reduce the environmental problem in large-area production of organic solar cells (OSCs).