NOVELTY - An optoelectronic device comprises an optoelectronic active layer (1140); a first electrode; and a second electrode. One of the first and second electrodes is a cathode (1120) comprising at least one first network of nanostructures and at least one of the first and second electrodes is transparent. The optoelectronic active layer is located between the first and second electrodes.    USE - As an optoelectronic device comprising a solar cell (claimed), particularly a thin-film solar cell comprising at least one nanostructure-film.    ADVANTAGE - The optoelectronic device comprising the nanostructure network has enhanced device performance due to the high work function of the nanostructure network and solar cell efficiency can be increased markedly by employing the nanostructure network as a transparent conductor. The multiple-active-layer solar cells expand solar cell capabilities by allowing the conversion of infrared-wavelength light. Unlike indium-tin-oxide, many nanostructure-films (e.g. those comprising single walled nanotube networks) allow transmission of infrared wavelength light. Accordingly, when combined with an appropriate active layer, electrode(s) comprising such films can harness this traditionally-untapped energy. Likewise, single-active-layer solar cells can be designed to convert solar energy from the infrared spectrum. The method of fabricating the optoelectronic device has the added advantage of allowing deposition of patterned films (e.g. where the poly(dimethylsiloxane) stamp is already patterned).    DETAILED DESCRIPTION - An optoelectronic device comprises: an optoelectronic active layer (1140); a first electrode; and a second electrode. One of the first and second electrodes is a cathode (1120) comprising at least one first network of nanostructures and at least one of the first and second electrodes is transparent. The optoelectronic active layer is located between the first and second electrodes. The optoelectronic device further comprises a polymer coating on the network of nanostructures, where the polymer coating fills several pores in the network of nanostructures; a first buffer layer (1130) between the cathode and the optoelectronic active layer; a second buffer layer (1150) between the anode and the optoelectronic active layer; a second active layer; a third electrode; and an electrode grid, superimposed on the network of nanostructures. The active layer comprises a photosensitive material that produces electricity when exposed to light. An INDEPENDENT CLAIM is included for fabricating the optoelectronic device involving depositing a first electrode on a substrate; depositing a first buffer layer on the first network of nanostructures; depositing a first active layer on the first buffer layer; depositing a second buffer layer on the active layer; and depositing a second electrode on the second buffer layer.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of a multilayer solar cell device architecture, where the cathode comprises nanostructures.    Nanostructure cathode (1120)    First buffer layer (1130)    Active layer (1140)    Second buffer layer (1150)    Transparent anode (1210)