NOVELTY - Preparation of segmented copolymer with main chain including fullerene comprises putting 50-100 mg polyalkoxythiophene with fullerene sealed end and with hydroxyl, 100-200 mg D,L-lactide, 5-10 mg tin octoate into 25 ml flask; adding 5-15 ml organic solvent while stirring magnetically; heating slowly to 60-100 degrees C; reacting for 36-72 hours; pouring methanol into reaction liquid; carrying out centrifugal separation at 3000-8000 revolutions per minute; and depressurizing and drying for 6-48 hours at room temperature .    USE - Preparation of segmented copolymer used in organic photovoltaic material.    ADVANTAGE - The segmented copolymer can spontaneously form micro-phase separation structure during film-forming process and at controllable scale so that electronic hole pairs can be separated efficiently on micro-phase interface. The micro-phase separation structure formed has good stability. The fullerene serving as electronic receptor material is sequentially arranged on interface of micro-phase so that usage of expensive fullerene can be saved extremely. The method has simple and convenient process, high film-forming quality, high investment-output ratio, and low cost and wide application. The segmented copolymer is environmental-friendly and high chemical performance.    DETAILED DESCRIPTION - Preparation of segmented copolymer with main chain including fullerene comprises:    (1) adding 50-150 ml anhydrous organic solvent, 5-25 mmol 2,5-dibromo-alkyl substituted thiophene or alkyl substituted thiophene and 5-25 ml tetrahydrofuran solution of methyl magnesium bromide having concentration of 1 M into 250 ml flask; back-flowing for 1-3 hour at 75 degrees C; adding 0.09-0.36 mmol diphenylphosphine propane nickel chloride; stirring for 0.5-6 hour; slowly adding 50-150 mg lithium aluminum hydride (LiAlH4) to end reaction; removing excessive LiAlH4 by dropping 1 M hydrochloric acid; pouring reaction liquid into methanol for deposition; carrying out centrifugal separation at 3000-8000 revolutions per minute; carrying out extraction in Soxhlet extractor using methanol, hexane and chloroform; finally, condensing chloroform solution of product and pouring it into methanol for deposition again; carrying out centrifugal separation at 3000-8000 revolutions per minute; depressurizing and drying at 30-60 degrees C to obtain polyalkoxy substituted thiophene;    (2) putting 200-400 mg polyalkoxythiophene into 100 ml reaction bottle; adding 10-20 ml anhydrous organic solvent; vacuumizing and inflating nitrogen to remove oxygen for three times; slowly heating to 50-90 degrees C until polyalkoxythiophene is completely dissolved while stirring magnetically; adding 1500-3000 mu l N-methyl formanilide and 250-500 mu l phosphorus oxychloride by disposable injector; stirring for 24-72 hours under nitrogen protection at 50-90 degrees C and cooling to 25 degrees C; adding prepared 10-20 ml saturated sodium acetate solution while stirring; stirring continuously for 2-6 hours; pouring reaction liquid into liquid separation hopper; putting upper layer of oil phase to 100-200 ml anhydrous ethanol for deposition; carrying out centrifugal separation at 3000-8000 revolutions per minute to obtain product; and vacuum-drying at 30-60 degrees C to obtain polyalkoxythiophene with aldehyde group sealed end;    (3) putting 100-200 mg polyalkoxythiophene with aldehyde group sealed end into 25 ml flask; adding 50-100 mg sarcosine and 25-50 mg fullerene and 5-15 ml organic solvent; repeatedly vacuumizing and inflating nitrogen to remove oxygen for three times; stirring at 30-60 degrees C until polyalkoxythiophene with aldehyde group sealed end is completely dissolved; heating to 80-120 degrees C for 24-72 hours; cooling to room temperature and using 25-75 ml methanol for deposition; carrying out centrifugal separation at 3000-8000 revolutions per minute for sediments; removing excessive fullerene using n-hexane to carry out Soxhlet extraction for sediment; and depressurizing and drying at room temperature to obtain polyalkoxythiophene with aldehyde group sealed end at productivity of 85-95%;    (4) putting 50-10 mg polyalkoxythiophene with fullerene sealed end into 25 ml flask; adding 10-20 mg parahydroxybenzaldehyde, 30-60 mg sarcosine and 5-10 ml organic solvent; heating to 80-120 degrees C while stirring; stirring magnetically for 24-72 hours; depositing using 25-50 ml methanol; carrying out centrifugal separation at 3000-8000 revolutions per minute; depressurizing and drying at room temperature to obtain polyalkoxythiophene with fullerene sealed end and with hydroxyl at productivity of 85%-95%;and    (5) putting 50-100 mg polyalkoxythiophene with fullerene sealed end and with hydroxyl, 100-200 mg D,L-lactide, 5-10 mg tin octoate into 25 ml of two-opening flask; adding 5-15 ml organic solvent while stirring magnetically; heating slowly to 60-100 degrees C; reacting for 36-72 hours; pouring methanol into reaction liquid for deposition; carrying out centrifugal separation at 3000-8000 revolutions per minute to obtain deposition; and depressurizing and drying for 6-48 hours at room temperature to obtain polyalkoxythiophene-fullerene-polylactic acid three-segmented copolymer at productivity of 50-60%.    An INDEPENDENT CLAIM is included for film-forming of segmented copolymer by dissolving 10-50 mg segmented copolymer into 0.5-5 ml 1,2-dichlorobenzene; stirring in presence of nitrogen protection; standing it for one night for future use; sequentially using acetone, chloroform and isopropanol to clean conductive substrate ultrasonically for 5-30 minutes; drying with nitrogen gas; dropping segmented copolymer to surface of conductive substrate to 0.25-0.85 mu m coat; after liquid drop is completely spread out, turning on rotary coating machine from 0 to 500-2000 revolutions per minute for 2-10 seconds; keeping at 500-2000 revolutions per minute for 20-60 seconds; transferring wet film to culture dish with cover at 0.25-0.85 mu m; controlling drying time for 0.5-2 hours; transferring dried film to nitrogen atmosphere for annealing for 1-5 hours at 120-180 degrees C, such that film after annealing is 20-100 nm thickness; preparing water/methanol solution of 0.5-5 M sodium hydroxide for future use, in which volume proportion of water/methanol is 1/4-4/1; decomposing polylactic acid chain section for 12-72 hours using water/methanol solution of sodium hydroxide at room temperature, respectively; cleaning using de-ionized water; and compressing nitrogen and drying it completely.