TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: In the photovoltaic device, where many cells of the composition or film, respectively connected to conductors, is adapted to produce a voltage between conductors when the cells are under solar illumination.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The metallic catalyst comprises nickel or palladium. The halothiophene organometallic reagent is zinc, magnesium or manganese organometallic reagent.    TECHNOLOGY FOCUS - POLYMERS - Preferred Process: In the preparation of the composition, the at least one of polythiophene and the fullerene is water soluble, and the water soluble polythiophene or fullerene is dissolved in water, then is contacted with the other of the polythiophene or fullerene, optionally also in solution in water or in a water-soluble organic solvent. The preparation of the composition further comprises copolymerizing with the dihalothiophene bearing a fullerene group a second dihalothiophene not bearing a fullerene group. In the preparation of the film, the composition is first dissolved in a solvent, then applied to a surface, and then the solvent is removed. Preferred Components: The polythiophene polymer is a regioregular polymer. The polythiophene polymer has a molecular weight of 1000-200000 Daltons. The polythiophene polymer is a 2,5-polythiophene. The polythiophene polymer comprises monosubstituted thienyl repeating units. The composition comprises a regioregular head-to-tail (HT)-2,5-polythiophene, comprising monosubstituted thienyl repeating units and the composition is substituted polythiophene compounds of formula (I). The composition comprises polythiophene-fullerene conjugate compounds of formula (II)-(VIII). In the composition: where there is on average more than one fullerene per polythiophene molecule; and where 0.1-50%, preferably 1-50% of the thienyl repeating units of the polythiophene bears a fullerene. The film further comprises additional light-gathering substances. In the preparation of the composition, the linker precursor group comprises: a carbene-generating moiety and the fullerene is an underivatized fullerene; or a nucleophilic group and the fullerene is a derivatized fullerene comprising an electrophilic group, where the derivatized fullerene is a fullerene carboxylic acid, carboxylic ester or carboxaldehyde, or fullerene alkyl halide or alkyl sulfonate ester, and the nucleophilic group is hydroxy, amino, thiol, carboxylic acid, organolithium group, Grignard reagent or Reformatsky reagent; or electrophilic group, and the fullerene is a derivatized fullerene comprising a nucleophilic group; or carboxylic acid, carboxylic ester or carboxaldehyde; or alkyl halide or alkyl sulfonate ester. In the preparation of the composition: where one of the linker precursor group and the derivatized fullerene comprises a carboxaldehyde or ketone group and the other comprises a phosphonium ylide, alpha -phosphonyl carbanion, organolithium reagent, Grignard reagent or Reformatsky reagent; and where one of the polythiophene linker precursor group and the fullerene comprises a cationic group and the other comprises an anionic group. The derivatized fullerene is (6,6)-phenyl-C61 butyric acid or (6,6)-phenyl-C61 butyric acid methyl ester, and the linker precursor group of the polythiophene comprises a carbinol, amino or carboxylic acid group. The polythiophene is a 2,5-HT-regioregular polythiophene 3-substituted with a hydroxyalkyl, aminoalkyl or alkylcarboxylate group. The polythiophene comprises a linker precursor group comprising a carboxylate or sulfonate group. The fullerene is fullerene compounds of formula (IX)-(XI). The dihalothiophene bearing a fullerene group is of formula (XII) or (XIII). The dihalothiophene is a 2,5-dichlorothiophene or 2,5-dibromothiophene, bearing a fullerene. In the photovoltaic device: where the polythiophene polymer and fullerene groups are mixed to form a composite material; and the polythiophene polymer and fullerene groups are formed in alternating layers.X = linker precursor group comprising a reactive group, preferably comprises optionally substituted 1-12C alkylene chain optionally further comprising unsaturation, cyclic groups and heteroatoms of O, NR2 or S, where the alkylene bearing a reactive group or derivative, where the reactive group is acid, ester, OH, amino or carbonyl, and the 1-12C alkylene chain terminally substituted with CO2R1 or COR1, OH, halo or NHR1;X1 = linker bonded covalently to at least one of the monosubstituted thienyl repeating units, where X1 can comprise covalent bonds and/or ionic bonds, preferably X1 is an alkylene chain, optionally containing a double bond, a triple bond or an aryl group or a heteroatom comprising O, NR1, S, S(O) or S(O)2, and the alkylene chain is optionally substituted with OH or carbonyl;FLR = fullerene bonded covalently or ionically via X1 to the regioregular polythiophene;n, m = 3-10000; anda = continuing chain with a terminal atom, each chain optionally bearing additional fullerenes linked to the regioregular polythiophene by linker X1;R1 = H or alkyl;R = H, alkyl or aryl (both optionally substituted);X2 = linker resulting from covalent or ionic bond formation between the linker precursor group of X and a fullerene reactant, preferably comprises an ester, an amide, an anhydride, an alkylation product or an olefination product, or comprises an alkylene chain in which is optionally disposed an ester, an amide, an anhydride, a double bond or a carbinol group, comprises at least one ionic bond or a bond between a cationic quaternary ammonium ion and an anionic carboxylate or sulfonate ion, where the cationic ion is comprised by a cationic fullerene derivative (IX), (X) or (XI);o, p = 0-12;Y1 = (CH2)r, (CH2)rCHOH(CH2)r, (CH2)rNR1(CH2)r, (CH2)rO(CH2)r, (CH2)rS(O)q(CH2)r or (CH2)rS(O)qNR1(CH2)r;r = 0-24;q = 0-2;R2 = H or alkyl;R3 = alkyl; eitherR4 = H, alkyl or aryl; orNR4R4 = 3-8 membered heterocyclyl (optionally substituted and optionally further comprising 1-3 addition heteroatoms of O, NR1 or S(O)q); andZ = halo. EXAMPLE - Poly(hypochlorous 6-(thiophen-3-yl)hexanoic anhydride) (0.5 g) was added in a 50 ml round bottom flask. Tetrahydrofuran (10 ml) and triethylamine (0.35 ml) were added and stirred for 1 hour. Fullerene-C60 (0.016 g) was added and stirred for 3 hours. The solvent was striped off. Dried under high vacuum for 1 hour to give poly(6-(3'-(4-fullerene-C60-butyl)-3''-(5-carboxy-pentyl)-(2,2';5',2'')terthiophen-4-yl)-hexanoic acid).