Significantly improved efficiency of organic solar cells incorporating Co3O4 NPs in the active layer

• DOI: 10.1007/s13204-018-0726-8
• Publication Date: 2018-03-19T10:41:34Z
• Authors: S. Amber Yousaf; M. Ikram; S. Ali
• Keywords: Active layer; Acceptor; Nanochemistry; Absorbance

Effect of various concentrations of fabricated cobalt oxide (Co3O4) nanoparticles (NPs) in the active layer of different donors and acceptors based hybrid organic bulk heterojunction-BHJ devices were investigated using inverted architecture. The organic active layer comprising different donors P3HT (poly(3-hexylthiophene-2,5-diyl) and PTB7 (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]][6,6]) and acceptor (phenyl-C-butyric acid methyl ester (PC60BM and PC70BM) materials. The incorporation of NPs in the binary blends of P3HT:PC60BM and PTB7:PC70BM enhanced the power conversion efficiency (PCE) of resulting ternary devices. This increase in PCE is mostly due to decrease in series resistance (Rs) with an optimum amount of Co3O4 in the organic photoactive layer. It was found that the ternary blend has higher absorbance relative to a binary blend of P3HT:PCBM. Addition of NPs in the active materials blend increased film roughness and form interpenetrating network to facilitate charges transportation in the active layer. The higher amount of NPs enhanced agglomerations which caused to break down the BHJ led to decrease the performance of the ternary devices.