TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The article further comprises an electron acceptor material.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The electron acceptor material comprise a material comprising fullerenes, inorganic nanoparticles, oxadiazoles, discotic liquid crystals, carbon nanorods, inorganic nanorods, polymers containing cyano groups and/or polymers containing trifluoromethyl groups. The electron acceptor material comprises a substituted fullerene, preferably (6,6)-phenyl C61-butyric acid methyl ester (C61-PCBM) or (6,6)-phenyl C71-butyric acid methyl ester (C71-PCBM).    TECHNOLOGY FOCUS - POLYMERS - Preparation: No preparation method is given. Preferred Components: The molar ratio of the first and second comonomer repeat units is at most 5:1, preferably 3:1. The first comonomer repeat unit comprises a silacyclopentadithiophene moiety of formula (1a). The second comonomer repeat unit comprises a cyclopentadithiophene moiety of formula (2a). The third comonomer repeat unit comprises a benzothiadiazole moiety of formula (3a). The polymer is an electron donor material.R1, R2 = H, 1-20C alkyl, 1-20C alkoxy, 3-20C cycloalkyl, 1-20C heterocycloalkyl, (hetero)aryl, halo, CN, OR, C(O)R, C(O)OR or SO2R, preferably 2-ethylhexyl or H;R3, R4 = H, 1-20C alkyl, 1-20C alkoxy, 3-20C cycloalkyl, 1-20C heterocycloalkyl, (hetero)aryl, halo, CN, OR, C(O)R, C(O)OR or SO2R; andR = H, 1-20C alkyl, 1-20C alkoxy, (hetero)aryl, 3-20C cycloalkyl or 1-20C heterocycloalkyl. EXAMPLE - 2,6-Bis(trimethylstannyl)-4,4-bis-(2-ethylhexyl)-4H-silolo(3,2-b:4,5-b')dithiophene (0.2766 g), 4,4-bis(2-ethylhexyl)-2,6-bis(trimethylstannyl)-4H-cyclopenta(2,1-b; 3,4-b')dithiophene (0.1353 g), 4,7-dibromo-2,1,3-benzothiadiazole (0.1575 g), tris(dibenzylideneacetone)-dipalladium (14.7 mg), and triphenylphosphine (33.7 mg) were dissolved in toluene (100 ml). The reaction was purged with argon for 15 minutes and was heated at 120 degrees C for 48 hours. The solvent was then removed under vacuum and the residue was dissolved in hot dichlorobenzene (100 ml). A solution of sodium diethyldithiocarbamate trihydrate (6 g in 170 ml water) was added. The mixture was stirred at 80 degrees C for 24 hours. After the organic layer was separated, washed with water, precipitated into methanol (800 ml) and worked up to give polymer of formula (Ia) (121 mg, approximately 41%).