Nanowire-based metamaterials electrodes for extremely fast charge collection

Hybrid nanostructures, comprising of a metal core and a semiconductor shell layer, shows great potential for a new generation of low-cost solar cells, due to their unique electronic and optical properties. However, experimental results have fallen far short of unltra-high efficiency (i.e. beyond Shockley-Queisser limit) predicted by theoretical simulation, limiting commercial application. Here, we experimentally design a non-transparent organic solar cell containing an array of Ag/ZnO nanowires, increasing internal quantum efficiency (IQE) by a factor of 2.5 compared with the planar counterpart, indicating a great enhancement of charge collection efficiency, due to the ultrafast Ag nanowire channels. Furthermore, we exploit this hybrid nanostructure as a perfect back reflector for semi-transparent solar cells, resulting in enhanced light absorption by a factor of 1.8 compared with the planar counterparts. The ability to enhance the charge collection and light absorption makes these Ag/ZnO nanostructures a flexible platform for the development of modern optoelectronic devices.