Template-directed synthesis of pyrite (FeS2) nanorod arrays with an enhanced photoresponse

A high solar conversion efficiency is the key characteristic required for any semiconductor material to be a candidate for photovoltaic applications. Although pyrite (FeS2) is considered a promising candidate because of its extremely high light absorption coefficient, its solar conversion efficiency still remains below 3%. We report here the design of a novel one-dimensional pyrite nanostructure to enhance the photoresponsive properties of pyrite. Well-aligned pyrite nanorod arrays were successfully grown on a transparent and conductive glass substrate of fluorine-doped tin oxide using a template-directed method. ZnO nanorod arrays were used as the initial template to produce Fe(OH)(3) nanotube arrays and then the Fe(OH)(3) nanotube arrays were used as a template to produce pyrite nanorod arrays. The pyrite nanorods had an average diameter of 130 nm and a length of 600 nm. The prepared pyrite nanorod films showed outstanding light absorption and enhanced photocurrents compared with nanoparticle FeS2 films. The excellent optical and photoelectrical performance of FeS2 nanorod films is attributed to the unique one-dimensional ordered architecture, which has large surface areas for light harvest and provides a direct and short pathway for charge transport, reducing the combination loss of photoelectrons. The method offers a new strategy for designing nanostructured materials with one-dimensional ordered architectures for high-performance photovoltaic devices.