TECHNOLOGY FOCUS - ELECTRONICS - Preferred Device: The photoelectric cell has a layer containing the composition or organic-semiconductor polymer between a primary electrode and a secondary electrode. The photoelectric cell has a hole transportation layer between primary electrode and the layer containing the organic-semiconductor polymer, an electron carrying layer between electrode and the layer containing the organic-semiconductor polymer. The primary electrode is a transparent electrode. The secondary electrode is a metal electrode.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compound: The n-type organic semiconductor molecule is fullerene or its derivative(s), preferably phenyl 61C butyric acid ester, diphenyl 62C bis(butyric acid ester), phenyl 71C butyric acid ester, phenyl 85C butyric acid ester, or thienyl 61C butyric acid ester.    TECHNOLOGY FOCUS - POLYMERS - Preparation: No general preparation given. Preferred Unit: The structural unit (I) is of formula (I-1). The organic-semiconductor polymer is a copolymer. The polymer further contains pentalene-containing structural unit of formula (II).X1=alkyl, cycloalkyl, aryl, aromatic heterocyclyl, or -NR3(R4), preferably NR3(R4);Q=Si, S, O, or N;G1,G2=Z1;R5=H, alkyl, cycloalkyl, aryl, aromatic heterocyclyl, or oxygen atom;andp'=0-2.(i) Coupling between Q and R5 is a double bond, when Q is Si and N; (ii) coupling between Q and R5 is single bond, when Q is S; (iii) when Q is O, p' is 0, and (iv) p' is 1 when Q is N. EXAMPLE - Small-pieces of magnesium (in mg) (60) was added into dry tetrahydrofuran (50 ml) in nitrogen atmosphere, and solution obtained by dissolving 4,6-dibromo-2-(octane-1-sulfonyl)thieno(3,4-d)(1,3)thiazole (95.1) in dry tetrahydrofuran (10 ml) was dropped and stirred. The solution was extracted in syringe after cooling, and suspension obtained by dispersing (1,3-bis(diphenylphosphino)propane) nickel salt (50 mg) to dry tetrahydrofuran (20 ml). The mixture was heated at 50 degrees C and reacted for 10 hours. The reaction mixture was added to 1N hydrochloric acid after cooling, the solid substance was filtered, and washed with water, methanol, and ethylenediaminetetraacetic acid aqueous solution. The crude product was filtered, reprecipitated, washed, and dried under vacuum to obtain polymer (53.3) having dispersion degree of 1.61, and weight average molecular weight (Mw) of 21000.