Hybrid GaAs-Nanowire–Carbon-Nanotube Flexible Photovoltaics

A simple method is described for the preparation of carbon nanotube (CNT) composite films containing Au nanoparticles, which act as adatom collection agents promoting the growth of core–shell p-n junction GaAs nanowires (NW), according to the vapor–liquid–solid mechanism. This approach for composite film formation requires no covalent modification of the CNTs. GaAs NWs obtained are randomly aligned with respect to the CNT substrate in a densely packed arrangement. Nanohybrid films, incorporating coaxial GaAs NWs as the active, light-harvesting medium are used in the fabrication of photovoltaic cells, exhibiting conversion efficiencies up to 0.32%. Doping experiments confirm that conduction is not dominated by Schottky barriers at contact interfaces. The NW/CNT solar cells are shown to retain function following bending up to a curve radius of 12.5 mm, illustrating the potential of these novel materials in flexible device applications.