TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The lanthanide atoms are bonded to at least one semimetal or transition metal via an oxygen atom. The compositions are formed by combining the rare earth metal nanoclusters, antenna ligand and polymer. Preferred Components: The nanoclusters are present in the size of 1-10 nm. The semimetal or transition metal comprises zirconium, titanium, gallium, aluminum, silicon, phosphorus, hafnium, vanadium, niobium, tantalum and/or tungsten. The molar ratio of lanthanide: semimetal or transition metal is 0.25-0.4. The luminescent rare earth metal nanocluster has an average particle diameter of 0.1-100 nm. The metal of the one or more other kinds of metal is coordinated to a rare earth metal via oxygen and the metal comprises one or more kinds of elements comprising Group 3B, Group 4A, and Group 5A metals. The metal coordinated to a rare earth metal and/or Period IV transition metal via oxygen or sulfur comprises one or more species of elements comprising aluminum, gallium, titanium, zirconium, hafnium, niobium, or tantalum. The rare earth metal comprises one or more species of elements comprising terbium, europium, neodymium, ytterbium, erbium, and praseodymium. The metals are coordinated to at least one kind of rare earth metals via sulfur. The coating has a thickness of more than 0.1 mu m. Preferred Compositions: The composition-3 further comprises an antenna ligand.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The device comprises: a substrate, and a layer of the compositions. The device further comprises a waveguide adjacent to the layer of the composition. The substrate is transparent to visible light and further comprises a second substrate that is transparent to visible light, where the layer of the compositions are disposed between the substrate and the second substrate. The substrate, second substrate, optional waveguide and layer of the compositions are each substantially planar (with width and length dimensions that are each at least 10 times greater than height), where the device comprises an edge parallel to height, and further comprises a photovoltaic cell disposed adjacent to the edge. The layer absorbs photons in a particular wavelength range and subsequently emits photons in a different wavelength range.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The sensitizer comprises: aromatic rings and carbonyl groups; and one or more species of elements comprising 4,4'-bis(N,N-dimethylamino)-benzophenone, 4,4'-bis(N,N-diethylamino)-benzophenone or 4,4'-bis(N,N-dimethylamino)-thiobenzophenone. The organic host material comprises methylmethacrylate or polymethylmethacrylate.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The polymer comprises a cyclic olefin copolymer (COC). EXAMPLE - Methylmethacrylate, europium-aluminum nanocluster (5 wt.%) and diethylacetophenone (0.5 wt.%) were mixed together. The resulting mixture was coated onto single-crystalline silicon solar cells by spin-coating at a rotation speed of 1000 rpm and polymerized to give corresponding composition.