ZnO Nanorod Arrays Coated with Eosin-Y at Different Concentrations for Inverted Bulk Heterojunction Organic Solar Cells

Abstract

Inverted bulk heterojunction organic solar cells based on vertically aligned dye-coated ZnO nanorods arrays were fabricated. The dye, Eosin-Y was wrapped on ZnO nanorods arrays with dye coating concentration ranging from 0.05 mM to 0.3 mM at room temperature for 1 h. The effects of Eosin-Y solution concentration on the performance of inverted bulk heterojunction organic solar cells based on a blend of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV) as donor and (6,6)-phenyl-C61 butyric acid methyl ester (PCBM) as acceptor with a structure of fluorine-doped tin oxide (FTO)/Eosin-Y coated ZnO nanorod arrays/MEHPPV:PCBM/Ag were investigated. Length, diameter and morphology of ZnO nanorods arrays were characterized. The optical properties of the Eosin-Y coated ZnO nanorod arrays were investigated and the organic solar cells were characterized by current–voltage measurements under 100 mW/cm2 simulated AM 1.5 G sunlight. It was found that current density, Jsc increased from 0.00134 mA/ cm2 to 0.0162 mA/ cm2 with increase in concentration of Eosin-Y from 0.05 mM to 0.3 mM. Solar cell with 0.3 mM Eosin-Y gave the highest power conversion efficiency, which is 7.15×10-4 %. Short circuit current density was 0.0162 mA/ cm2 and the corresponding open circuit voltage was 0.17 V.