Efficiency enhancement of organic solar cells using peroxo-polytitanic acid coated silver nanowires as transparent electrodes

Abstract

Solution-processed transparent electrodes made from silver-nanowires and peroxo-polytitanic (PPT) acid gel were developed for enhancing efficiency of organic solar cells. The electronic and optical properties of multilayer silver nanowires were significantly improved through the interconnection layers of amorphous titanium oxide (TiO_x) from PPT acid gel. The AgNW–TiO_x composite film showed averaged 92.14% optical transmittance with only 16.01 Ω sq⁻¹ sheet resistance. Combining the transparent electrodes with poly(3-hexylthiophene):[6,6]-phenyl-C₆₁-butyric acid methyl ester (P3HT:PC₆₁BM) blend, the efficiency of organic solar cells was 1.45 times that of devices using an ITO electrode. Optical simulations verified that the improvement was attributed to the enhanced near-field absorption and substantial scattering of incident light resulted from the random nature of the AgNW–TiO_x core–shell nanostructure.