TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Component: The article comprises an electrically conductive layer coated on the diffraction foil that is configured as at least a portion of an electrode. The photovoltaic cell comprises a photoactive material comprising an electron donor material and an electron acceptor material. The photoactive material comprises a photosensitized interconnected nanoparticle material. The diffraction foil is configured to direct incoming light to the photoactive layer. It is disposed between two substrates. The diffraction foil is configured so that, when light impinges on the diffraction foil, the diffraction foil reflects the pattern. The article comprises a security card, an identification card, a greeting card, a business card, an advertising board, a poster, or a sign.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Material: The electron acceptor material comprises inorganic nanoparticles and/or inorganic nanorods. The photosensitized interconnected nanoparticle material comprises selenides, sulfides, tellurides, titanium oxides, tungsten oxides, zinc oxides, and/or zirconium oxides. The photoactive material comprises amorphous silicon or copper indium gallium selenide.    TECHNOLOGY FOCUS - METALLURGY - Preferred Component: The diffraction foil comprises a metal, preferably aluminum, chromium, copper, silver, gold, or its alloy.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Material: The electron acceptor material comprises a material from fullerenes, oxadiazoles, discotic liquid crystals, and/or carbon nanorods. The electron donor material comprises discotic liquid materials.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The diffraction foil comprises a polymer. The electron acceptor material comprises polymers containing CN groups and/or polymers containing carbon fluoride (CF3) groups. The electron donor material comprises polythiophenes, polyphenylenes, polyphenylvinylenes, polysilanes, polythienylvinylenes, or polyisothianaphthalenes.