Fabrication of PTB7:PC71BM bulk hetero junction polymer solar cells by airbrush spray-coating technique

In the present work, we have demonstrated high performance organic solar cells with spray coated active layers. The influence of nanomorphology on power conversion efficiency of Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl] [3-fluoro-2-[(2-ethylhexyl)carbonyl] thieno[3,4-b]thiophenediyl]] (PTB7):[6,6]-phenyl-C71-butyric acid (PC71BM) methyl esters bulk heterojunction solar cells was presented. Active layers were prepared with chlorobenzene mixed with small volume of 1,8-diiodooctane as a cosolvent prepared by spray coating using conventional handheld airbrushes. The surface morphology of the active layers deposited with various spray coating time was examined using atomic force microscopy. The resulting devices were measured under AM 1.5G (100 mW/cm²) conditions in ambient atmosphere. The optimized spray-coated PTB7:PC71BM film shows high solar cell performance with short circuit current density of 13.90 mA/cm², fill factor of 57.4 % and power conversion efficiency of 5.96 %.