TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The energy of the highest occupied molecular orbital of the guest is farer from the vacuum energy level than that of the host. The electron acceptor material and the host are selected so that an electron transfer occurs between the electron acceptor material and the host upon illumination of the electron donor material at at least one wavelength. The weight ratio guest/host is 0.001-0.20. The electron acceptor layer and the electron donor layer form an planar heterojunction. Preferred Photovoltaic Structure: The photovoltaic structure comprises a layer where the semiconductor electron acceptor material and the semiconductor electron donor material are mixed to form a bulk heterojunction; and further comprises a first conductive layer on a first side of the photovoltaic structure and second conductive layer on a second side of the photovoltaic structure, where the first and second conductive layers are selected so that at least one of the layer is at least partially transparent. Preferred Method: The method (M1) further involves: providing a substrate having a first conductive layer, optionally applying contacts on the first conductive layer, optionally applying a first set of at least one intermediate layer on the first conductive layer, applying the photovoltaic structure on the first conductive layer or on top of the first set of at least one intermediate layer, optionally applying a second set of at least one intermediate layer on the photovoltaic structure, and optionally applying a second conductive layer on the photovoltaic structure or on top of the second set of intermediate layers, where the first and second conductive layers are selected so that at least one is at least partially transparent.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The guest is selected from lanthanide metal chelate, heavy metal porphyrin, heavy metal phthalocyanine or iridium metal chelate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The host comprises an organic semiconductor; or aromatic tertiary amine compound. The organic semiconductor has at least one moiety in its chemical structure selected from phenylene, thiophenylene, selenophenylene, vinylene, acene, porphyrin, phthalocyanine, flurorene or indenofluorene. The guest is selected from diketone derivative of formula (Ie); and tris(2-(2-pyridinyl)phenyl-C,N)-iridium (Ir(Ppy)3), Iridium (III) bis(4,6-di-fluorophenyl-pyridinato-N,C2)picolinate (Firpic), platinum octaethylporphyrin (PtOEP) or benzyl (preferably Ir(ppy)3, (PtOEP) or (Firpic)). The tertiary amine compound is selected from N,N'-diphenyl benzidine ( alpha -NPD) and N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-benzidine (TPD). The host material is 4,4'-N,N'-dicarbazole-biphenyl (CBP).R,R'=H, CH3, ethyl, propyl, -O-R''or N(R'')2;R''=H, CH3, ethyl or propyl.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The host is selected from poly(para-phenylene vinylene) derivative, poly(para-phenylene) derivative, biphenyl derivative, polythiophene derivative or polyselenophene derivative, and (preferably polyparaphenylene derivative). The electron donor material comprises a poly(para-phenylene vinylene) derivative of formulae (Ia)-(Id). The polyparaphenylene derivative is selected from polyfluorene derivative, indenofluorene derivative and ladder polyparaphenylene derivative.R=8-12C linear or branched alkyl chain;x,y,z=integer such that molecular weight is 10000-80000 g/mol;n=integer such that molecular weight is 10000-80000 g/mol. EXAMPLE - No suitable example given.