Effect of Eosin-Y Coating Temperature on the Performance of Inverted Bulk Heterojunction Organic Solar Cells

Inverted type bulk heterojunction organic solar cell based on ZnO nanorod arrays have been used to overcome the degradation problem of conjugated polymer and low work function electrode. ZnO nanorods and Eosin-Y are widely used to increase the charge mobility and light absorbance, respectively. The effects of Eosin-Y coating temperature (30 - 50 degrees C) on the performance of organic solar cells based on a blend of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV) as donor and (6,6)-phenyl-C-61 butyric acid methyl ester (PC61BM) as acceptor with a structure of fluorine-doped tin oxide (FTO)/Eosin-Y coated ZnO nanorod arrays/MEHPPV:PCBM/Ag were investigated. By using FTO as a substrate, sol-gel and spin coating method was used to deposit ZnO seed layer on FTO surface. The ZnO nanorods were then grown on the ZnO seed layer by chemical bath deposition method and coated with dye by immersing the substrates into Eosin-Y solution at different temperatures. The result shows that absorption of Eosin-Y coated ZnO nanorods increased with dye coating temperature. The optimum power conversion efficiency of beta = 1.24 x 10(-2) % was achieved at dye coating temperature 50 degrees C under 100 mW/cm(2) simulated AM 1.5 G sunlight.