NOVELTY - A photoelectric conversion element (107) consists of a pair of electrodes (101,105), an active layer (103) arranged between the electrodes, and an electron extraction layer (104) arranged between at least one electrode and active layer. The active layer contains a copolymer having a (dithia-sila-cyclopenta-pentalenyl)-thieno-pyrrole-dione-containing repeating unit (I). The electron extraction layer comprises a compound containing group 16 element.    USE - Photoelectric conversion element e.g. solar cell used in solar modules (all claimed). Uses include but are not limited to rooftops, toplights, walls, curtain walls, doorposts, windows, slats of blinds, vegetable factories, outer walls of parking lots, sound insulation walls of highways, outer walls of water purification plants, bonnets of motor vehicles, motor drives, and electrical components.    ADVANTAGE - The photoelectric conversion element has excellent photoelectric conversion efficiency, durability, and workability. The element reduces illumination cost by 30%.    DETAILED DESCRIPTION - A photoelectric conversion element consists of a pair of electrodes, an active layer arranged between the electrodes, and an electron extraction layer arranged between at least one electrode and active layer. The active layer contains a copolymer having a (dithia-sila-cyclopenta-pentalenyl)-thieno-pyrrole-dione-containing repeating unit of formula (I). The electron extraction layer comprises a compound containing group 16 element, of formula: (R21-E(=X)-)p-R23.    R1=aryl, alkyl or alkenyl (all optionally substituted);    R2-R5=H, halo, or aryl, alkyl or alkenyl (all optionally substituted);    E=PR22, S, S(=O) or C;    p=1 or more;    R21,R22=arbitrary substituent;    R21+R22=ring;    R23=p-valent hydrocarbyl, p-valent heterocyclyl, or p-valent group formed by connecting hydrocarbyl and heterocyclyl (all optionally substituted);and    X=group 16 atom.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the photoelectric conversion element.    Electrodes (101,105)    Hole extraction layer (102)    Active layer (103)    Electron extraction layer (104)    Photoelectric conversion element (107)