TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The device further comprises component for photon energy down-shifting or down-conversion absorbs light in the UV-wavelength region and emits light in the blue wavelength region. Preferred Process: The step of arranging involves contacting the device with the object, or using the device as cover of the object.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The medium comprises at least two pairs of sensitizer and emissive components, respectively, where each pair has a defined absorption wavelength region and a defined emission wavelength region, and the pairs of sensitizer and emissive components, respectively, differ from each other in at least their respective absorption wavelength region. The medium additionally comprises a further component for photon energy down-shifting or photon energy down-conversion, where the down-shifting or down-conversion component also being distributed within the matrix, and the down-shifting or down-conversion component being capable of absorbing light of a defined wavelength region and emitting light at a wavelength region longer than the defined wavelength region. The medium is arranged in a single layer or waveguide or shape suitable to cover parts or all of a surface of an object, upon which the light is incident, e.g. a solar cell. The single layer or waveguide or shape has cylindrical or paralleliped or triclinic symmetry. The medium is arranged in several layers, where each layer has a different pair of sensitizer and emissive components in it, and one layer of the several layers comprises the further component for photon energy down-shifting or down-conversion. The layer that comprises the further component for photon energy downshifting or down-conversion is devoid of any pair of sensitizer and emissive component. The medium comprises one pair of sensitizer and emissive component, which absorbs in the green wavelength region and emits in the blue wavelength region and the medium comprises another pair of sensitizer and emissive component, which absorbs in the red wavelength region and emits in the blue wavelength region. The medium comprises one pair of sensitizer and emissive component, which is perylene and palladium octaethylporphyrin and another pair of sensitizer and emissive component, which is perylene and platinum octaethylporphyrin. The medium comprises perylene as a component for photon energy down-conversion. The fluid has a viscosity of 0.59x 10-3-1x 106 Pa.s. The matrix is: an organic or inorganic glass with a viscosity of 1x 103-1x 1017 Pa.s; or an inorganic or organic gel having a viscosity of greater than or equal to 1x 10-1 Pa.s. The matrix is a viscous liquid having a viscosity of greater than or equal to 0.59x 10-3 Pa.s. The first and second component is a first and second organic compound, respectively. The first component is neither covalently bonded nor complexed to the second component. The first and second organic compounds are different compounds. The first and the second organic compound is a carbon-containing compound, with the proviso that it is not a hydrogen-free chalcogenide of carbon, or its derivative, a salt-like carbide, a metallic carbide or a metal-carbonyl. The emissive component's emitting light at the second wavelength region lambda 2 is due to an up-conversion process based on direct or sequential two-photon excitation or on direct or sequential multi-photon excitation or on excitation of molecules populating high vibrational states ("hot-band absorption"), which up-conversion process occurs upon absorption of light by the first component at the first wavelength region lambda 1. The emissive component's emitting light at the second wavelength region lambda 2 is due to an up-conversion process based on a triplet-triplet annihilation process between photoexcited molecules of the emissive component and/or based on a triplet-triplet annihilation process between photo-excited molecules of the first component. The second wavelength region lambda 2 is 360-750 nm and the first wavelength region lambda 1 is 450-1600 nm. The first component is an organic dye or molecule having a populated triplet or mixed triplet-singlet state, a two-photon-absorbing-dye, an optical limiting compound, another molecule with a populated triplet state or an optical limiting compound e.g. a fullerene, or carbon nanotubes. The second component is an organic dye. The first and second organic dyes are the same or different. The first and/or second organic dye is organic dyes with populated triplet states or capable of direct and/or sequential two-photon excitation, organic dyes capable of direct and/or multi-photon excitation, organic dyes capable of non-linear absorption or organic dyes capable of hot-band absorption. The organic dye, in particular the first organic dye, is organic molecules having populated triplet states and especially metal-organic complexes having populated triplet states, where the metal (T) is lithium, magnesium, aluminum, titanium, vanadium (vanadium oxide), manganese, iron, cobalt, nickel, copper, zinc, gallium, ruthenium, palladium, silver, rhenium, osmium, iridium, platinum, lead and/or uranium (uranium oxide) containing organic complexes, to ensure wavelength control. The first organic dye is compounds with a populated triplet state, including: porphyrins including extended porphyrins, texaphyrins, sapphyrins, orangerins, any carbon-bridged pyrrolic system, substituted porphyrins and metals (T); phthalocyanines including extended phthalocyanines, substituted phthalocyanines, and the phthalocyanins containing metals including (T); and/or benzopyridines, benzopyrizines, quinolates and hydroxyquinolates, acetyl-acetonates, substituted benzopyridines, benzopyrizines, quinolates and hydroxyquinolates, and acetyl-acetonates. The second organic dye is compounds showing fluorescence emission of 360-750 nm, in particular e.g. anthracenes, tetracenes, pentacenes, perylenes substituted anthracenes, tetracenes, pentacenes, perylenes phenyl (bi-, tri-phenyl)-bridged anthracenes, tetracenes, pentacenes, perylenes fluorenes, thiophenes, polyfluorenes and oligofluorenes, optionally with side-chain pattern and their copolymers, polyparaphenylenes including polyparaphenylene vinylene, and polyphenylene ethinylenes. The first and the second organic dye are such that a populated triplet state of the first organic dye is at an energy level allowing a triplet-triplet annihilation process and the subsequent transfer of energy to an excited singlet state of the second dye. The first and second component are: green couple (9,10-diphenylanthracene/2,7,8,12,13,17,18-octaethylporphyrin palladium); red couple (9,10-bis(phenylethynyl)anthracene/meso-tetraphenyl-tetrabenzoporphyrin palladium); near infra red couple (9,10-bis(phenylethynyl)naphthacene/meso-tetraphenyl-octamethoxide-tetranaphtho(2,3)porphyrin palladium); direct red-to-blue couple (dibenz(de,kl)anthracene (perylene)/meso-tetraphenyl-tetrabenzoporphyrin palladium); direct infrared-to-green couple (4,4'-bis(5-tetracenyl)-1,1'-biphenylene/meso-tetraphenyl-octamethoxide-tetranaphtho(2,3)porphyrin palladium); or infrared-to-yellow couple (5,6,11,12-tetraphenylnaphthacene (rubrene)/tetraantraporphyrin palladium). The first and second components are homogeneously distributed within the matrix. The first and second components are encapsulated in particles having average dimensions of 5 nm to 999 mu m, preferably 10 nm-999 mu m. The particles have a surface, which is functionalized by functional groups to allow distribution of the particles within the matrix, where the functional groups are preferably hydrogen or groups of formula (-(CH2)nCH3), (-(CH2)n-COOR), (-(CH2)n-OR), (-(CH2)n-SR), (-(CH2)n-N(R)2) or (-((CH2)p-O)n-CH3).R = alkenyl or alkynyl (both optionally substituted), halo such as Cl, Br, F or I, NO2, NH2, CN, SO3H or OH; andn = 0-10.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The matrix is transparent at 300-1600 nm. The matrix is a solid with elastic, plastic, viscoelastic or viscoplastic properties. The matrix is made of one or more materials comprising organic oligomers, which have a finite number of monomeric units, and co-oligomers, which is comprised of a mixture of monomeric units including optionally substituted styrenes, phenylenes, phenylene diamines, phenylene diols, methyl methacrylates, phenols, acrylic acids, vinyls, such as vinyl alcohol or vinyl chloride, lactic acids, carbohydrates, carbonates, imides, amides such as acryl amide, olefins such as ethylene and propylene, olefin oxides such as ethylene oxide or propylene oxide, olefin glycols such as ethylene glycol and propylene glycol, terephthalic acids, epsilon-caprolactams, urethanes, silanes, siloxanes and/or their substituted and functionalized forms. The matrix optionally and additionally includes one or more organic solvents or water to vary, adjust and control the viscosity of the medium. The organic gel is an organic physical gel having non-covalent bonds or is a chemical gel having covalent bonds and preferably being crosslinked, where crosslinking is achieved by irradiation and/or by addition of crosslinking chemicals. The gel contains linear and branched polymers (A) including poly(styrenes), (poly)phenylenes, poly(naphthalate), poly(terephthalate), poly(olefin-naphthalate) and poly(olefin-terephthalate) such as poly(ethylene naphthalate), poly(ethylene terephthalate), poly(ether imides), poly(ether ketones), poly(hydroxyl-butyrates), poly(phenylene diamines), poly(phenylene diols), poly(methyl methacrylates), poly(phenols), poly(acrylic acids), poly(vinyls) such as poly(vinyl alcohols) or poly(vinyl chlorides), poly(lactic acids), poly(carbohydrates), poly(carbonate), poly(imide), poly(amide) such as poly(acryl amide), olefins such as poly(ethylene) and poly(propylene), poly(olefin oxides) such as poly(ethylene oxide) or poly(propylene oxide), poly(olefin glycols) such as poly(ethylene glycol) and poly(propylene glycol), poly(terephthalic acids), poly(epsilon-caprolactam), poly(urethanes), polysilanes and/or poly(siloxanes), or their blends. The matrix is a solid or glass having a viscosity of greater than or equal to 1x 103 Pa.s. The matrix is made of a thermoplastic polymer or copolymer (block, alternating and/or graft copolymers) or its mixture and/or with one or more suitable solvents to control and adjust viscoelasticity or plastoelasticity of the medium. The matrix is made of polymer or copolymer including block, alternating and/or graft copolymers with molecular weights of 103 to approximately 109, comprising (A). The matrix is made of a thermosetting plastic, which is polyester resins, epoxy resins, preferably two- component epoxy resins, acrylics, polyimides, melamine resins, and phenol-formaldehyde resins. The matrix is made of an elastic solid and more specifically a polymer elastomer comprising polyacrylic rubbers, silicone rubbers, fluorosilicone rubbers, fluoroelastomers, perfluoroelastomers, polyether-block- amides, or olefin rubbers. The matrix does not take part in a photon energy up-conversion process upon irradiation of the medium.