TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Device: The device further comprises first electrode on one side of the composition of carbon nanotubes and of the hole conductor. It also comprises a solid inorganic crystalline or glassy substrate, or a metal foil substrate, preferably a stainless steel foil substrate, or a polymer substrate pre-coated with the first or the second electrode. The first electrode has a first work function, and a second electrode on another side of the composition of carbon nanotubes and of the hole conductor. The second electrode has a higher work function than the first work function. Preferred Property: The band gap of the hole conductor is 1-3 eV, preferably 1.75-2.25 eV. The hole conductor is semiconducting organic materials with a band gap of above 1 eV and pi-orbital higher in energy than the highest occupied molecular orbital (HOMO) of the carbon nanotubes.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The hole conductor is a conjugated polymer or a blend of at least two conjugated polymers. It can be polymethacrylates and derivatives, e.g. bis(diarylamino)biphenyl functionalised methacrylates and/or its copolymers, polyaniline and derivatives, polyphenylene and derivatives, polyphenylene vinylene and derivatives, e.g. poly (2-methoxy, 5-(3', 7'-dimethyloctyloxy)-1,4-phenylene vinylene (MDMO-PPV), polythiophene and derivatives, copolymers of triphenyl diamine derivatives and trimethoxyvinylsilane, poly(3,4-ethylenedioxythiophene: polystyrene sulfonic acid) (PEDOT:PSS), polyacetylene and/or it derivatives, polyparaphenylene and/or its derivatives, polypyrrole and/or its derivatives, polyparaphenylene sulfide and/or its derivatives, polycarbazole and/or its derivatives, polyisothianaphene and/or its derivatives, poly(1,6-heptadiyne) and/or its derivatives, or polyquinoline and its derivatives.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The carbon nanotubes are a mixture of metallic and semiconducting carbon nanotubes, preferably only semiconducting carbon nanotubes. They are a mixture of multi-walled and single-walled carbon nanotubes, preferably only single-walled carbon nanotubes. The first and/or the second electrode is coated with an evaporated layer of fluoride or acetate, e.g. lithium fluoride, cesium fluoride or CH3COOLi (sic). Preferred Dimension: The carbon nanotubes have a diameter of 0.5-2 nm. The band gap of the carbon nanotubes is 0.5-1 eV.