Plasmonic nano-particles mediated energy harvesting in thin-film organic solar cells

A Cd-doped ZnO nano-composite (Cd:ZnO) was synthesized using wet chemistry, and then incorporated into the photo-active layer of a thin film organic solar cell (TFOSC) to assist photon harvesting. The nano-composite (NC) formed different sized nano-structures that are beneficial to optical absorption and charge transport processes in the TFOSC. The effects on the NC were studied using a solar absorber medium composed of a poly(3-hexylthiophene) (P3HT) and 6-6-phenyl-C61-butyric acid methyl ester (PCBM) blend with standard device architecture: ITO/PEDOT:PSS/P3HT:PCBM/LiF/Al. The electrical and optical properties of the photoactive films were investigated at various doping levels of Cd:ZnO NC in the medium. The composite showed interesting local surface plasmon resonance, which significantly impacted on the performance of the cells. Consequently, the power conversion efficiency of the TFOSC grew by 84% compared to the reference cell. It is also noted that Cd:ZnO is environmentally stable and compatible for solution device processing.