TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: No preparation method is given. Preferred Components: The donor substance and the acceptor substance are part of respective layers of a donor-acceptor bilayer or part of a donor-acceptor mixed layer (bulk heterojunction). The photoactive material further comprises at least one semiconductor material. The donor substance comprises or consists of at least one (I), and the acceptor substance comprises or consists of at least one of fullerenes or its derivatives, preferably C60, C70 and (6,6)-phenyl-C61-butyric acid methyl ester or 3,4,9,10-perylenetetracarboxy-bisbenzimidazole (PTCBI). Preferred Definitions:    X1, X2 = H, F or Cl;    Y1, Y2 = O or S; and    A1, B1 = phenyl, chloro-phenyl, pyridyl, pyrazinyl, pyrimidinyl, furanyl, thienyl, 1-propyl-1H-pyrrolyl, benzofuranyl, benzo(b)thienyl, 1-propyl-1H-indolyl, biphenyl, 4-phenyl-pyridyl, 2-phenyl-pyrimidinyl, 2-phenyl-(1,3,5)triazinyl, quinolinyl, 9,9-dibutyl-9H-fluorenyl, dibenzofuranyl, dibenzothienyl, 9-ethyl-9H-carbazolyl, 4-propyl-4H-dithieno(3,2-b;2',3'-d)pyrrolyl, dithieno(3,2-b;2',3'-d)thiophenyl, naphthyl, pyrenyl, (1,1';4',1'')terphenyl, anthracenyl, phenanthrenyl, fluoranthenyl, biphenylenyl, acenaphthylenyl, perylenyl, naphthacenyl, chrysenyl, 2-phenyl-thiophenyl, 5-phenyl-(2,2')bithiophenyl, 2-phenyl-thieno(3,2-b)thiophenyl, 4,4-dimethyl-2-phenyl-4H-cyclopenta(2,1-b;3,4-b')dithiophenyl, 2-phenyl-4-propyl-4H-dithieno(3,2-b;2',3'-d)pyrrolyl, 2-phenyl-dithieno(3,2-b;2',3'-d)thiophenyl, 2-phenyl-7-oxa-3,4-dithia-cyclopenta(a)pentalenyl, 2-phenyl-7H-3,4-dithia-7-sila-cyclopenta(a)pentalenyl, trimethyl-phenylethynyl-silanyl, naphthalen-1-yl-phenyl-diazenyl, 2,3-dioxo-1,4-dimethyl-1,4-dihydro-pyrazinyl, benzo(1,2,5)thiadiazolyl, methylsulfanyl-phenyl, trifluoromethyl-phenyl, nitrophenyl, N,N-diethyl-amino-phenyl, N-(2-ethoxy-phenyl)-benzamide, 9H-fluorenyl, ((E)-2-phenylvinyl)benzene, methoxy-phenyl, (phenylethynyl)benzene, 2,5-diphenyl-thiophenyl, 2-(5-phenyl-thiophen-2-ylmethylene)-malononitrile, (Z)-2,3-diphenyl-acrylonitrile, benzo(de)benzo(4,5)imidazo(2,1-a)isoquinolin-7-one, 3-phenyl-2-pyridin-4-yl-propionitrile, 2-phenyl-9H-fluorenyl, 1-methyl-pyrrolyl, thiazolyl or 10-ethyl-10H-phenothiazinyl.    EXAMPLE - No suitable example given.