NOVELTY - The thin-film photovoltaic device comprises a structured substrate (102) including a base substrate (104) and an array of structure features (106), a first electrode layer (108) disposed adjacent to the structured substrate and shaped to conform to the array of structure features, an active layer (116) disposed adjacent to the first electrode layer and shaped to conform to the first electrode layer, and a second electrode layer (114) disposed adjacent to the active layer so that the first electrode layer and the second electrode layer have an interlocking configuration.    USE - The thin-film photovoltaic device e.g. solar cell is useful in optoelectronic devices such as photoconductors, photo-detectors, light-emitting diodes and lasers.    ADVANTAGE - The thin-film photovoltaic device exhibits improved solar conversion efficiency, enhanced charge collection efficiency, reduced reflection losses of incident solar radiation and enhanced optical absorption, and can be easily and efficiently manufactured at low-cost using the structured substrate.    DETAILED DESCRIPTION - The thin-film photovoltaic device comprises a structured substrate (102) including a base substrate (104) and an array of structure features (106), a first electrode layer (108) disposed adjacent to the structured substrate and shaped to conform to the array of structure features, an active layer (116) disposed adjacent to the first electrode layer and shaped to conform to the first electrode layer, and a second electrode layer (114) disposed adjacent to the active layer so that the first electrode layer and the second electrode layer have an interlocking configuration. The active layer includes a set of photoactive materials. The lateral dimension of the array of structure features is 100 nm to 1 mu m. The longitudinal dimension of the array of structure features is 1-10 mu m. An aspect ratio of the array of structure features is 5-100. A spacing of nearest-neighbor ones of the array of structure features is 500 nm to 10 mu m. The array of structure features corresponds to an array of nanorods extending from the base substrate. The array of nanorods includes a metal oxide or a metal chalcogenide. The first electrode layer includes an array of protrusions shaped in accordance with the array of nanorods, and an array of recesses shaped in accordance with the array of pores. The second electrode layer includes an array of recesses complementary to the array of protrusions, and an array of protrusions complementary to the array of recesses. The array of structure features corresponds to an array of pores. The first electrode layer or the second electrode layer is transparent in the visible range. An electrically conductive layer is disposed between the first and second electrode layers, and includes a set of nanoparticles including en electrically conductive material. An INDEPENDENT CLAIM is included for a method for forming a structured substrate.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a thin-film photovoltaic device.    Structured substrate (102)    Base substrate (104)    Array of structure features (106)    First electrode layer (108)    Second electrode layer (114)    Active layer. (116)