TECHNOLOGY FOCUS - POLYMERS - Preferred Units: The group of N-type organic semiconductor unit is group having fullerene structure, nitrogen-containing heterocyclic group, or aryl group having electron-withdrawing group. The group of P-type organic semiconductor unit is a heterocyclic group containing sulfur, nitrogen, oxygen, silicon, boron, selenium, tellurium or phosphorus as ring atom. The group of P-type organic semiconductor unit is heterocyclic group chosen from groups of formulae (a1)-(a51).asterisk=connection position with polymer principal chain/side chain, or bivalent coupling group, or single bond.(i) When forming a polymer principal chain, at least 2 bonds are used for polymer principal chain formation, and a bivalent coupling group, hydrogen atom, or substituent is coupled with remaining bonds; and (ii) When a bond is used for polymer principal chain formation, the bond is at a position at which a polymer principal chain is conjugated. EXAMPLE - 50 mg Polymer of formula (AA) having a weight average molecular weight of 7.8x 104, a number average molecular weight of 4.2x 104, a lambda -max of 670 nm, and a glass transition temperature of greater than 300 degrees C was dissolved in 10 mL dichloroethane. 10 mg Nitrobenzene and 496 mg triethylamine were added. 296 mg Acrylic acid chloride was added under ice-cooling and stirred at room temperature for 8 hours. The reaction mixture was opened in 500 mL acetonitrile and filtered after 30-minute stirring. 30 mg polymer of formula (AA1) was obtained by crystallizing the obtained solid with chloroform-methanol after purification with silica gel column chromatography. The obtained polymer had a weight average molecular weight of 7.9x 104, a number average molecular weight of 4.3x 104, a lambda -max of 670 nm, and a glass transition temperature of greater than 300 degrees C. 100 mg Fullerene was dissolved in 10 mL pyridine. 150 mg 4-Hydroxybutyl acrylate was added under ice-cooling and stirred at room temperature for 12 hours. The reaction mixture was opened in 500 mL acetonitrile and filtered after 30-minute stirring. The obtained solid was purified using silica gel column to obtain a fullerene polymer. 10 mg Polymers (AA1) and 15 mg fullerene polymer were dissolved in 1 mL o-dichlorobenzene, and filtered. The filtrate was applied on poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) layer to form a photoelectric-conversion layer. A photoelectric cell using the formed layer had a short-circuit density of 12.8 mA/cm2, an open circuit voltage of 0.71 V, a curve factor of 56%, an electric power generation efficiency of 5.1%, and an electric power generation efficiency retention rate of 80%.