Self-Organized Formation of Embossed Nanopatterns on Various Metal Substrates: Application to Flexible Solar Cells

Abstract We report metal substrate dependent formation of honeycomb-like nanopatterns via a versatile anodization method. During the anodization of metal foils, the well-known formation of well-aligned metal oxide nanotube arrays are observed, and honeycomb-like nano-hole patterns are successfully obtained after stripping the oxide nanotube array layers. Interestingly, the sizes of the nano-hole patterns are dependent upon the starting metal substrate for the anodization. By simple alternation of a metal substrate for anodization, it is possible to tune the radius and interpore distance of the resulting nanosized hole patterns. As one of applications for nanopatterned metal substrates, flexible dye-sensitized solar cells are fabricated, and the positive effects of the nanopatterned substrate on cell efficiency are investigated.